JP2016085970A - Light-emitting element, light-emitting device, display device, electronic device, and illuminating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light-emitting element having an electrode layer with a high reflectance and having a large light emission efficiency.SOLUTION: A light-emitting element comprises: a first electrode layer; a second electrode layer; and an EL layer provided between the first and second electrode layers. The first electrode layer has a conductive layer, and an oxide layer in contact with the conductive layer. The conductive layer has the function of reflecting light. The oxide layer has In, and M (M represents Al, Si, Ti, Ga, Y, Zr, Sn, La, Ce, Nd or Hf). The content of M included in the oxide layer is equal to or larger than that of In.SELECTED DRAWING: Figure 1

Description

  One embodiment of the present invention relates to a light-emitting element, or a light-emitting device, a display device, an electronic device, and a lighting device each including the light-emitting element.

  Note that one embodiment of the present invention is not limited to the above technical field. The technical field of one embodiment of the invention disclosed in this specification and the like relates to an object, a method, or a manufacturing method. Alternatively, one embodiment of the present invention relates to a process, a machine, a manufacture, or a composition (composition of matter). Therefore, the technical field of one embodiment of the present invention disclosed in this specification more specifically includes a semiconductor device, a display device, a liquid crystal display device, a light-emitting device, a lighting device, a power storage device, a memory device, a driving method thereof, Alternatively, the production method thereof can be given as an example.

  In recent years, research and development of light-emitting elements using electroluminescence (EL) have been actively conducted. The basic structure of these light-emitting elements is such that a layer containing a light-emitting substance (EL layer) is sandwiched between a pair of electrodes. Light emission can be obtained from a light-emitting substance by applying a voltage between the electrodes of this element.

  Since the light-emitting element described above is a self-luminous type, a light-emitting device using the light-emitting element has advantages such as excellent visibility, no need for a backlight, and low power consumption. Further, the light emitting device can be manufactured to be thin and light and has advantages such as high response speed.

  In addition, when the above light-emitting element is used for a display device, a method of providing an EL layer having a function of emitting different colors on each sub-pixel in a pixel (hereinafter referred to as a separate coloring method), and a sub-pixel in the pixel. For example, a method in which a common EL layer having a function of emitting white light is provided in a pixel and a color filter having a function of transmitting light of a different color is provided in each sub-pixel (hereinafter referred to as a white EL + color filter method, The emission color of the common EL layer is not limited to white).

  As an advantage of the white EL + color filter method, the EL layer can be made common to all the sub-pixels, so that the loss of the material of the EL layer and the cost required for pattern formation can be reduced as compared with the separate coating method. Therefore, the display device can be manufactured with low cost and high productivity. Next, in the separate coloring method, a blank space is required between the pixels in order to prevent the materials of the EL layers of the sub-pixels from mixing with each other, but the white EL + color filter method does not require the blank space. Realizing a display device with higher pixel density and higher definition.

  The light-emitting element can provide various emission colors depending on the type of the light-emitting substance contained in the EL layer. In particular, when considering application to illumination or a white EL + color filter type display device, a light emitting element capable of obtaining white light emission or light emission close to it with high efficiency is required. In addition, a light-emitting element with low power consumption is required.

  In order to improve the light extraction efficiency from the light emitting device, a method of increasing the light intensity at a specific wavelength by adopting a micro optical resonator (microcavity) structure using the resonance effect of light between a pair of electrodes is proposed. (For example, refer to Patent Document 1).

  In addition, in order to reduce power consumption of the light-emitting element, a metal oxide having a high work function is used for the electrode that does not extract light from the pair of electrodes, thereby reducing voltage loss due to the electrode, A method for reducing the drive voltage has been proposed (see, for example, Patent Document 2).

JP 2012-182127 A JP 2012-182119 A

  In order to improve the light extraction efficiency in the light-emitting element, it is desirable to use a material having high reflectivity for the electrode that does not extract light from the pair of electrodes. In order to reduce the driving voltage of the light emitting element, it is desirable to use a material having a high work function for the anode. However, it is difficult to select a stable material having a high reflectance and a high work function and suitable for an electrode of a light emitting element.

  Therefore, an attempt has been made to improve the light extraction efficiency of the light-emitting element and reduce the driving voltage by forming an electrode structure in which a material having a high reflectance and a material having a high work function are stacked. However, when two different types of materials are stacked, electrons may be exchanged at the interface between the two different types of materials due to the difference in ionization tendency. In addition, when an oxide is used for one of the stacked materials, oxygen may be exchanged at the interface between two different materials. Such exchange of electrons and exchange of oxygen cause corrosion of the electrode material. When the electrode material is corroded, the stress of the electrode layer formed by the electrode material changes, which may cause a defect due to film peeling, decrease in the light emission efficiency of the light emitting element, or increase in the drive voltage. . Moreover, these also cause an electrical short circuit of the light emitting element and a light emitting failure.

  As a method of manufacturing a display device capable of full color display, the separate coating method requires a process of depositing a specific light emitting layer only on necessary sub-pixels using a shadow mask having a fine opening. The accuracy (also referred to as alignment accuracy) of disposing the opening at a desired position (also referred to as alignment) is required to be high. In addition, since a display device capable of high-definition display requires higher alignment accuracy, there is a problem in that the yield in manufacturing the display device decreases and the manufacturing cost increases.

  On the other hand, the white EL + color filter method does not require the shadow mask having the fine openings as described above, so that the display device can be manufactured with high productivity. However, in the white EL + color filter system, since a light emitting layer having a function of emitting white light is formed in common for each sub-pixel, light emission of a color unnecessary for each sub-pixel is included. For this reason, the white EL + color filter method has a problem in that the light use efficiency is lower than that of the separate coating method. Therefore, it is required to increase the light emission efficiency of the white light emitting element. In addition, it is required to increase the productivity of light emitting elements. In addition, a light-emitting element with high light utilization efficiency is demanded.

  In order to obtain white light emission with a light-emitting element including an EL layer having one light-emitting unit, it is necessary to efficiently emit light-emitting substances that emit different colors simultaneously in a single EL layer. Light emission obtained from the EL layer is affected by the distribution of regions in which recombination of electrons and holes injected into the EL layer occurs. For example, if the recombination region is biased to a light emitting layer containing one light emitting substance, light emission from the other light emitting substance is weakened. That is, the emission color of the EL layer changes depending on the region where recombination of electrons and holes injected into the EL layer occurs. Therefore, in order to control the emission color exhibited by the EL layer, it is important to control a region where recombination of electrons and holes injected into the EL layer occurs.

  In other words, since the emission color exhibited by the EL layer can be controlled by controlling the region where recombination of electrons and holes injected into the EL layer occurs, the light-emitting layer has a function of emitting white light. It becomes possible to extract light having a desired emission color from the light emitting element. Therefore, a light-emitting layer having a function of emitting white light is commonly formed on each sub-pixel of the display device, and a region where recombination of electrons and holes of each sub-pixel is controlled, and the emission color of each sub-pixel is controlled. If different emission colors can be extracted from each sub-pixel by controlling the light-emitting element, a light-emitting element with high light utilization efficiency can be manufactured.

  In view of the above problems, an object of one embodiment of the present invention is to provide a novel light-emitting element. Another object is to provide a novel light-emitting element with high emission efficiency. Another object is to provide a novel light-emitting element with reduced power consumption. Another object is to provide a novel light-emitting element including an EL layer having a plurality of light-emitting layers. Another object is to provide a light-emitting element in which an electron and hole recombination region of an EL layer is controlled. Another object is to provide a novel method for manufacturing a light-emitting element.

  Note that the description of the above problems does not disturb the existence of other problems. Note that one embodiment of the present invention does not necessarily have to solve all of these problems. Problems other than those described above are naturally apparent from the description of the specification and the like, and it is possible to extract problems other than the above from the description of the specification and the like.

  One embodiment of the present invention is a light-emitting element including a first electrode layer, a second electrode layer, and an EL layer provided between the first electrode layer and the second electrode layer, The first electrode layer includes a conductive layer and an oxide layer in contact with the conductive layer. The conductive layer has a function of reflecting light. The oxide layer includes In and M (M is Al Si, Ti, Ga, Y, Zr, Sn, La, Ce, Nd, or Hf), and the content of M contained in the oxide layer is greater than or equal to the content of In A light-emitting element is characterized.

  Another embodiment of the present invention is a light-emitting element including a first electrode layer, an EL layer over the first electrode layer, and a second electrode layer over the EL layer, The electrode layer includes a conductive layer and an oxide layer in contact with the conductive layer. The conductive layer has a function of reflecting light. The oxide layer includes In and M (M is Al, Si, Ti, Ga, Y, Zr, Sn, La, Ce, Nd, or Hf), and the content of M contained in the oxide layer is greater than or equal to the content of In It is a light emitting element.

  Another embodiment of the present invention is a light-emitting element including a first electrode layer, an EL layer in contact with the first electrode layer, and a second electrode layer in contact with the EL layer, The first electrode layer includes a conductive layer and an oxide layer in contact with the conductive layer. The conductive layer has a function of reflecting light. The oxide layer includes In and M (M is Al, Si, Ti, Ga, Y, Zr, Sn, La, Ce, Nd or Hf), and the content of M contained in the oxide layer is greater than or equal to the content of In It is a light emitting element characterized by these.

  Another embodiment of the present invention is a light-emitting element including a first electrode layer, a second electrode layer, a third electrode layer, and an EL layer, and the EL layer includes: The first electrode layer is provided between the electrode layer and the second electrode layer, and between the second electrode layer and the third electrode layer. The first electrode layer includes a conductive layer and an oxide layer in contact with the conductive layer. The conductive layer has a function of reflecting light, the oxide layer is In, and M (M is Al, Si, Ti, Ga, Y, Zr, Sn, La, Ce, Nd Or M represents in the oxide layer, and the content of M in the oxide layer is greater than or equal to the content of In.

  Another embodiment of the present invention is a light-emitting device including a first electrode layer, an EL layer over the first electrode layer, a second electrode layer over the EL layer, and a third electrode layer. An EL layer is provided over a third electrode layer, the first electrode layer includes a conductive layer and an oxide layer in contact with the conductive layer, and the conductive layer transmits light. The oxide layer has a function of reflecting, and the oxide layer has In and M (M represents Al, Si, Ti, Ga, Y, Zr, Sn, La, Ce, Nd, or Hf) and is oxidized. The light-emitting element is characterized in that the M content in the physical layer is greater than or equal to the In content.

  Another embodiment of the present invention includes a first electrode layer, an EL layer in contact with the first electrode layer, a second electrode layer in contact with the EL layer, and a third electrode layer. In the light-emitting element, the EL layer is provided in contact with the third electrode layer, the first electrode layer includes a conductive layer and an oxide layer in contact with the conductive layer. , Has a function of reflecting light, and the oxide layer has In and M (M represents Al, Si, Ti, Ga, Y, Zr, Sn, La, Ce, Nd, or Hf). The light-emitting element is characterized in that the M content in the oxide layer is greater than or equal to the In content.

  Another embodiment of the present invention is a semiconductor device including a first electrode layer and a transistor. The first electrode layer includes a conductive layer and an oxide layer in contact with the conductive layer. The conductive layer has a function of reflecting light, and the oxide layer includes In and M (M is Al, Si, Ti, Ga, Y, Zr, Sn, La, Ce, Nd, or Hf. And the content of M contained in the oxide layer is greater than or equal to the content of In.

  In the above structure, the transistor includes a channel region in the oxide semiconductor layer, and the oxide semiconductor layer includes In and M (M is Al, Si, Ti, Ga, Y, Zr, Sn, La, Ce). , Nd or Hf).

  In each of the above structures, the third electrode layer preferably includes an oxide different from the structure of the oxide layer.

  In each of the above structures, the first region sandwiched between the first electrode layer and the second electrode layer is the second region sandwiched between the second electrode layer and the third electrode layer. It is preferable that the color of light that can be exhibited by the two regions and light of a different color can be exhibited.

  In each of the above structures, the EL layer includes a first light-emitting layer and a second light-emitting layer, and the first light-emitting layer includes a first compound having a function of emitting light, The light emitting layer preferably has a second compound having a function of exhibiting light.

  In the above structure, one of the first compound and the second compound has a function of converting singlet excitation energy into light emission, and the other of the first compound and the second compound has triplet excitation energy. It is preferable to have a function capable of converting to light emission.

  In each of the above structures, the first compound preferably exhibits light of a color different from the color of light exhibited by the second compound.

  In each of the above structures, the conductive layer preferably contains Al or Ag.

  In each of the above structures, the second electrode layer preferably includes at least one of In, Ag, and Mg.

  In each of the above structures, the oxide layer preferably further contains Zn.

  In each of the above configurations, M is preferably Ga.

  In each of the above structures, the oxide layer preferably contains In, Ga, and Zn.

  Another embodiment of the present invention is a display device including the light-emitting element having any of the above structures, and the display device includes a transistor that switches the light-emitting element, and the transistor includes a channel region in the oxide semiconductor layer. And the oxide semiconductor layer includes In and M (M represents Al, Si, Ti, Ga, Y, Zr, Sn, La, Ce, Nd, or Hf). Display device.

  In the above structure, it is preferable that the oxide layer and the oxide semiconductor layer have the same element.

  Another embodiment of the present invention is a display device including the light-emitting element having any of the above structures, a color filter, or a transistor, or an electronic device including the display device having any of the above-described structures and a housing or a touch sensor. A lighting device including a light emitting element having a structure and a housing or a touch sensor is also included in the category. A light emitting device in this specification refers to an image display device or a light source (including a lighting device). In addition, a connector in which a connector such as an FPC (Flexible Printed Circuit) or TCP (Tape Carrier Package) is attached to the light emitting device, a module in which a printed wiring board is provided at the end of TCP, or a COG (Chip On Glass) A module on which an IC (integrated circuit) is directly mounted by a method may have a light emitting element.

  According to one embodiment of the present invention, a novel light-emitting element can be provided. Alternatively, according to one embodiment of the present invention, a novel light-emitting element with high emission efficiency can be provided. Alternatively, according to one embodiment of the present invention, a novel light-emitting element with reduced power consumption can be provided. Alternatively, according to one embodiment of the present invention, a novel light-emitting element including an EL layer having a plurality of light-emitting layers can be provided. Alternatively, a light-emitting element in which an electron and hole recombination region of the EL layer is controlled can be provided. Alternatively, according to one embodiment of the present invention, a novel method for manufacturing a light-emitting element can be provided.

  Note that the description of these effects does not disturb the existence of other effects. Note that one embodiment of the present invention does not necessarily have all of these effects. It should be noted that the effects other than these are naturally obvious from the description of the specification, drawings, claims, etc., and it is possible to extract the other effects from the descriptions of the specification, drawings, claims, etc. It is.

FIG. 6 is a schematic cross-sectional view illustrating a light-emitting element of one embodiment of the present invention. FIG. 6 is a schematic cross-sectional view illustrating a light-emitting element of one embodiment of the present invention. FIG. 6 is a schematic cross-sectional view illustrating a light-emitting element of one embodiment of the present invention. FIG. 6 is a schematic cross-sectional view illustrating a light-emitting element of one embodiment of the present invention. FIG. 6 is a schematic cross-sectional view illustrating a light-emitting element of one embodiment of the present invention. FIG. 6 is a schematic cross-sectional view illustrating a light-emitting element of one embodiment of the present invention. FIG. 6 is a schematic cross-sectional view illustrating a light-emitting element of one embodiment of the present invention. 6A and 6B illustrate a crystal model used for calculation according to one embodiment of the present invention. FIG. 6 is a schematic cross-sectional view illustrating a method for manufacturing a light-emitting element according to one embodiment of the present invention. FIG. 6 is a schematic cross-sectional view illustrating a method for manufacturing a light-emitting element according to one embodiment of the present invention. FIG. 10 is a schematic cross-sectional view illustrating a light-emitting element of one embodiment of the present invention. 4A and 4B each illustrate correlation of energy levels in a light-emitting layer according to one embodiment of the present invention. 4A and 4B each illustrate correlation of energy levels in a light-emitting layer according to one embodiment of the present invention. 4A and 4B are a top view and cross-sectional schematic views illustrating a display device of one embodiment of the present invention. FIG. 10 is a schematic cross-sectional view illustrating a display device of one embodiment of the present invention. FIG. 10 is a schematic cross-sectional view illustrating a display device of one embodiment of the present invention. FIG. 10 is a schematic cross-sectional view illustrating a display device of one embodiment of the present invention. FIG. 10 is a schematic cross-sectional view illustrating a display device of one embodiment of the present invention. 4A and 4B are a block diagram and a circuit diagram illustrating a display device of one embodiment of the present invention. FIG. 6 is a perspective view illustrating an example of a touch panel of one embodiment of the present invention. FIGS. 5A and 5B are cross-sectional views illustrating an example of a display device and a touch sensor of one embodiment of the present invention. FIG. 6 is a cross-sectional view illustrating an example of a touch panel of one embodiment of the present invention. 4A and 4B are a block diagram and a timing chart of a touch sensor of one embodiment of the present invention. FIG. 6 is a circuit diagram of a touch sensor of one embodiment of the present invention. FIG. 10 is a perspective view illustrating a display module of one embodiment of the present invention. 6A and 6B illustrate an electronic device of one embodiment of the present invention. FIG. 10 illustrates a lighting device of one embodiment of the present invention. The figure explaining the reflectance of an electrode layer based on an Example. The cross-sectional schematic diagram explaining the light emitting element based on an Example. 6A and 6B illustrate current efficiency-luminance characteristics of a light-emitting element according to an example. 6A and 6B illustrate an electroluminescence spectrum of a light-emitting element according to an example. 6A and 6B illustrate current efficiency-luminance characteristics of a light-emitting element according to an example. 8A and 8B illustrate luminance-voltage characteristics of a light-emitting element according to an example. 6A and 6B illustrate an electroluminescence spectrum of a light-emitting element according to an example. 6A and 6B illustrate current efficiency-luminance characteristics of a light-emitting element according to an example. 8A and 8B illustrate luminance-voltage characteristics of a light-emitting element according to an example. 6A and 6B illustrate an electroluminescence spectrum of a light-emitting element according to an example.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and various changes can be made in form and details without departing from the spirit and scope of the present invention. Therefore, the present invention should not be construed as being limited to the description of the embodiments below.

  Note that the position, size, range, and the like of each component illustrated in the drawings and the like may not represent the actual position, size, range, or the like for easy understanding. Therefore, the disclosed invention is not necessarily limited to the position, size, range, or the like disclosed in the drawings and the like.

  In this specification and the like, the ordinal numbers attached as the first and second are used for convenience and may not indicate the order of steps or the order of lamination. Therefore, for example, the description can be made by appropriately replacing “first” with “second” or “third”. In addition, the ordinal numbers described in this specification and the like may not match the ordinal numbers used to specify one embodiment of the present invention.

  Further, in this specification and the like, in describing the structure of the invention with reference to the drawings, the same reference numerals are used in different drawings.

  Color is generally defined by the three elements of hue (corresponding to the wavelength of monochromatic light), saturation (brightness, that is, the degree of whiteness), and brightness (brightness, that is, the intensity of light). is there. Further, in this specification, the color may indicate only one of the three elements described above or only two elements selected arbitrarily. In the present specification, the two light colors being different means that at least one of the above three elements is different, and further, the shape of the spectrum of two lights or the relative intensity ratio of each peak. Including that the distribution is different.

  In this specification and the like, blue light emission has at least one emission spectrum peak in a wavelength band of 420 nm or more and 490 nm or less, and green light emission has at least one emission spectrum peak in a wavelength band of 500 nm or more and less than 550 nm. The yellow light emission has at least one emission spectrum peak in the wavelength band of 550 nm or more and less than 590 nm, and the red light emission has at least one emission spectrum peak in the wavelength band of 590 nm or more and 740 nm or less. It is.

In this specification and the like, a fluorescent material is a material that emits light in the visible light region when relaxing from the lowest level of a singlet excited state (S ₁ level) to a ground state. A phosphorescent material is a material that emits light in the visible light region at room temperature when relaxing from the lowest level (T ₁ level) of a triplet excited state to the ground state. In other words, a phosphorescent material is one of materials that can convert triplet excitation energy into visible light.

  Note that in this specification and the like, room temperature refers to any temperature of 0 ° C. to 40 ° C.

In this specification and the like, a transparent conductive film is a film having a function of transmitting visible light and having conductivity. For example, the transparent conductive film includes an oxide conductor film typified by indium tin oxide (hereinafter referred to as ITO), an oxide semiconductor film, or an organic conductor film containing an organic substance. Examples of the organic conductor film containing an organic substance include a film containing a composite material obtained by mixing an organic compound and an electron donor (donor), and a composite material obtained by mixing an organic compound and an electron acceptor (acceptor). And the like. The resistivity of the transparent conductive film is preferably 1 × 10 ⁵ Ω · cm or less, more preferably 1 × 10 ⁴ Ω · cm or less.

  In this specification and the like, the terms “film” and “layer” can be interchanged with each other. For example, the term “conductive layer” may be changed to the term “conductive film”. Alternatively, for example, the term “insulating film” may be changed to the term “insulating layer” in some cases.

(Embodiment 1)
In this embodiment, a light-emitting element of one embodiment of the present invention will be described below with reference to FIGS.

<1. Configuration Example 1 of Light-Emitting Element>
1A and 1B are cross-sectional views illustrating a light-emitting element of one embodiment of the present invention. A light-emitting element 150 illustrated in FIG. 1A includes an electrode layer 101, an EL layer 100, and an electrode layer 102. The electrode layer 101 includes a conductive layer 101a and an oxide layer 101b in contact with the conductive layer 101a.

  1A includes a hole injection layer 111, a hole transport layer 112, a light-emitting layer 120, an electron transport layer 118, and an electron as shown in FIG. The injection layer 119 may be included.

  Note that the light-emitting element in this embodiment is described using the electrode layer 101 as an anode and the electrode layer 102 as a cathode; however, the structure of the light-emitting element is not limited thereto. That is, the electrode layer 101 may be a cathode, the electrode layer 102 may be an anode, and the stacking of each layer between the electrode layers may be reversed. In other words, the hole injection layer 111, the hole transport layer 112, the light emitting layer 120, the electron transport layer 118, and the electron injection layer 119 may be stacked in this order from the anode side.

  In addition, each layer may be formed in the EL layer between the pair of electrodes in accordance with the function thereof, and is not limited thereto. That is, the EL layer between the pair of electrode layers reduces the hole or electron injection barrier, improves the hole or electron transport property, inhibits the hole or electron transport property, or suppresses the quenching phenomenon by the electrode. It is good also as a structure which has a layer which has the function of being able to suppress.

≪Example of electrode layer configuration≫
The conductive layer 101a included in the electrode layer 101 has a function of reflecting light. By using a material containing aluminum (Al) or silver (Ag) for the conductive layer 101a, the reflectance of the conductive layer 101a can be increased, and the light emission efficiency of the light-emitting element 150 can be increased. Note that Al is preferable because the material cost is low and pattern formation is easy, and thus the manufacturing cost of the light-emitting element can be reduced. Further, Ag has a particularly high reflectance, so that the light emission efficiency of the light emitting element can be increased, which is preferable.

The oxide layer 101b that is in contact with the conductive layer 101a included in the electrode layer 101 preferably has conductivity. The resistivity of the oxide layer 101b is preferably 1 × 10 ⁵ Ω · cm or less, and more preferably 1 × 10 ⁴ Ω · cm or less. When the oxide layer 101b has conductivity, the injection property of electrons or holes from the electrode layer 101 to the EL layer 100 can be increased, and the driving voltage of the light-emitting element 150 can be reduced.

  The oxide layer 101b preferably has a function of transmitting light. Since the oxide layer 101b has a function of transmitting light, the reflectance of the electrode layer 101 can be increased, so that the light emission efficiency of the light-emitting element 150 can be increased.

  By using an oxide containing indium (In) for the oxide layer 101b, the conductivity of the oxide layer 101b can be increased. In addition, the light transmittance of the oxide layer 101b can be increased.

  When the conductive layer 101a included in the electrode layer 101 is in contact with the oxide layer 101b over the conductive layer 101a, a difference in ionization tendency between the material used for the conductive layer 101a and the material used for the oxide layer 101b May occur.

  The magnitude of the ionization tendency can be determined by using the value of the standard electrode potential as an index. For example, since the standard electrode potential of Al is −1.68 V and the standard electrode potential of In is −0.34 V, Al has a higher ionization tendency than In. When a material containing Al is used for the conductive layer 101a and an oxide containing In is used for the oxide layer 101b, a difference in ionization tendency between the material containing Al and the oxide containing In increases. Electrons are exchanged between materials, and galvanic corrosion occurs. In addition, since the bonding force between Al and oxygen is stronger than the bonding force between In and oxygen, oxygen is transferred between the material containing Al and the oxide containing In, and the material containing Al and In In some cases, an oxide of Al is formed at the interface with the oxide having bismuth. Since the oxide of Al has low conductivity, the conductivity of the electrode layer 101 is lowered, which is a cause of an increase in driving voltage of the light-emitting element 150. In addition, when electrolytic corrosion occurs, the stress of the electrode layer changes, so that film peeling may occur.

  Therefore, in one embodiment of the present invention, an oxide including In and an element having a higher binding energy to oxygen than In is used for the oxide layer 101b. Alternatively, an oxide containing In and an element that has a higher ionization tendency than In is used for the oxide layer 101b. Alternatively, an oxide containing In and an element whose standard electrode potential is lower than that of In is used for the oxide layer 101b. That is, the oxide layer 101b includes In, a stabilizer M (M is Al, silicon (Si), titanium (Ti), gallium (Ga), yttrium (Y), zirconium (Zr), tin (Sn), lanthanum ( La), cerium (Ce), neodymium (Nd), or hafnium (Hf)) is used.

  In addition, the content of the stabilizer M included in the oxide layer 101b is preferably equal to or greater than the content of In. With such a structure, the bonding force between the metal element and oxygen in the oxide layer 101b becomes stronger, and exchange of oxygen between the oxide layer 101b and the conductive layer 101a can be prevented. . Therefore, the occurrence of electrolytic corrosion in the electrode layer 101 can be prevented, and the driving voltage of the light emitting element 150 can be reduced. Moreover, in order to produce a stable electrode layer, it is more preferable that the content of the stabilizer M is larger than the content of In.

  Table 1 shows standard electrode potentials of examples of elements that can be used for In and stabilizer M. Table 2 shows calculated values of the binding energy of Ga and oxygen, which are examples of elements that can be used for In and oxygen, and the stabilizer M.

  The standard electrode potentials shown in Table 1 are cited from “Chemical Handbook Basic Edition II Rev. 4th Edition, Tables 12 and 40 (II 465 to II 468 pages), Maruzen Co., Ltd.”. The difference in the standard electrode potential between the oxide layer and the conductive layer containing Al, as shown in Table 1, in which the element having a standard electrode potential smaller than In is used as the stabilizer M and the oxide layer containing In has an In. Therefore, a redox reaction hardly occurs between the oxide layer and the conductive layer. That is, transfer of electrons or transfer of oxygen between the conductive layer containing Al and the oxide layer containing In can be prevented.

  For the calculation of the binding energy between the metal element and oxygen shown in Table 2, the first principle calculation software VASP (The Vienna Ab initio simulation package) was used. 8A and 8B are crystal models used for the calculation. The effect of inner-shell electrons was calculated by the Projector Augmented Wave (PAW) method. As the functional, GGA / PBE (Generalized-Gradient-Application / Perdew-Burke-Ernzerhof) was used. Table 3 shows the calculation conditions.

The binding energy with oxygen (E _binding (M−O)) was calculated from Equation (1). In the formula (1), M represents In or Ga, n is the number of atoms depending on the model size, and n = 16 in this calculation. E _atom (M) and E _atom (O) are the total energies of each atom, and E _tot (M _2n O _3n ) is the total energy of the M ₂ O ₃ crystal model. As shown in FIG. 8B, in the In ₂ O ₃ crystal, In is only 6-coordinate and O is only 4-coordinate, and the bond strength of In—O can be regarded as constant. On the other hand, as shown in FIG. 8A, β-Ga ₂ O ₃ crystals include tricoordinate and tetracoordinate O, and tetracoordinate and hexacoordinate Ga. The bond energy is not uniform, but here, in order to simplify the calculation, the bond energy of Ga—O was calculated using the average value.

  As a result of the calculation, as shown in Table 2, the Ga—O bond energy is larger than the In—O bond energy. Therefore, it can be said that Ga has a stronger bond with oxygen.

Note that in an oxide containing a plurality of metal elements such as an In—Ga—Zn oxide, oxygen is bonded to two or three metal elements as compared to a case where oxygen is bonded to only a single metal element. There are many cases. Therefore, next, the bond energy between the metal element and oxygen (MO) was calculated for the In: Ga: Zn = 1: 1: 1 (atomic ratio) crystal model. The number of atoms in the model was 84, and the conditions shown in Table 3 were used for the calculation. The binding energy (E _{B, M−O} ) was calculated from Equation (2). In Formula (2), the binding energy (EB _{, MO} ) depends on the distance between MO (dMO). A _{0, M} , a _{1, M} , a _{2, M} in Equation (2) were calculated by fitting so that S in Equation (3) was minimized. Incidentally, IGZO formula (4): _{V O} represents the In-Ga-Zn oxide model existing oxygen vacancy _{(V O)} is in the In-Ga-Zn oxide, a _{V O} generated energy in the model E (V _O ).

  The binding energies at the average distances of Ga—O and In—O of 0.195 nm and 0.220 nm were calculated to be 2.33 eV and 1.80 eV, respectively. Therefore, even in an oxide including a plurality of metal elements such as an In—Ga—Zn oxide, the bond energy of Ga—O is larger than the bond energy of In—O, and Ga has a bond with oxygen. It can be said that it is strong.

  As described above, an element having a lower standard electrode potential than In or an element having a higher ionization tendency than In is used as the stabilizer M for the oxide layer 101b, or an element having a binding energy with oxygen stronger than In is oxidized as the stabilizer M. When used for the physical layer 101b, transfer of electrons or transfer of oxygen between the oxide layer 101b containing In and the conductive layer 101a containing Al can be suppressed. That is, by using an oxide including In and a stabilizer M (M represents Al, Si, Ti, Ga, Y, Zr, Sn, La, Ce, Nd, or Hf) for the oxide layer 101b. In addition, the occurrence of electrolytic corrosion in the electrode layer 101 can be prevented, and the driving voltage of the light emitting element 150 can be reduced. In addition, since the content of the stabilizer M included in the oxide layer 101b is greater than or equal to the content of In, oxygen exchange between the oxide layer 101b and the conductive layer 101a can be effectively prevented. Is preferred.

  Since the standard electrode potential of Ag is 0.80 V, Ag has a smaller ionization tendency than In. Therefore, it is preferable to use a material containing Ag for the conductive layer 101a because oxygen is hardly transferred from the oxide layer 101b to the conductive layer 101a. Note that also in this case, the oxide layer 101b includes an oxide having In and a stabilizer M (M represents Al, Si, Ti, Ga, Y, Zr, Sn, La, Ce, Nd, or Hf). By using a material, the oxygen bonding force in the oxide layer 101b becomes stronger, so that a more stable electrode layer 101 can be manufactured.

  The electrode layer 102 has a function of transmitting light. By using a material containing at least one of In, Ag, and magnesium (Mg) for the electrode layer 102, the transmittance of the electrode layer 102 can be increased, and the light emission efficiency of the light-emitting element 150 can be increased.

  In the case where the electrode layer 102 has a function of transmitting light and a function of reflecting light, the light emission efficiency of the light-emitting element 150 can be increased by the microcavity effect. Therefore, it is preferable to use a material containing at least one of In, Ag, and Mg for the electrode layer 102.

  The electrode layer 101 may have a function of reflecting light and a function of transmitting light. In that case, the conductive layer 101a included in the electrode layer 101 is preferably formed to have a thickness enough to transmit light. Further, when the electrode layer 101 has a function of reflecting light and a function of transmitting light, the electrode layer 102 preferably has a function of reflecting light, and particularly preferably has Ag having a high reflectance.

  In addition, the color purity of the light-emitting element 150 can be improved by providing a color filter over the electrode layer from which light is extracted. Therefore, the color purity of the display device including the light-emitting element 150 can be increased.

<2. Configuration Example 2 of Light-Emitting Element>
Next, structural examples different from the light-emitting element 150 illustrated in FIGS. 1A and 1B are described below with reference to FIGS.

  2A and 2B are cross-sectional views illustrating a light-emitting element of one embodiment of the present invention. In FIGS. 2A and 2B, portions having the same functions as those shown in FIG. 1 have the same hatch pattern, and the symbols may be omitted. Moreover, the same code | symbol is attached | subjected to the location which has the same function, and the detailed description may be abbreviate | omitted.

  2A and 2B, the electrode layer 101 includes a conductive layer 101a having a function of reflecting light, and an oxide layer in contact with the conductive layer 101a. 101b and a transparent conductive film 101c over the oxide layer 101b.

  In the case where the electrode layer 101 is used as an anode, a material having a high work function is preferably used for the transparent conductive film 101c. In the case where the electrode layer 101 is used as a cathode, it is preferable to use a material having a low work function for the transparent conductive film 101c. By including such a transparent conductive film 101c, the electrode layer 101 becomes an electrode with good carrier injection into the EL layer.

  2B, the light-emitting layer 120 may have a structure in which a light-emitting layer 120a and a light-emitting layer 120b are stacked. By using a light emitting material having a function of exhibiting different light emission colors for the light emitting layer 120a and the light emitting layer 120b, light emission having a plurality of light emission colors can be obtained simultaneously from the light emitting element 172. In addition, a light-emitting material is preferably selected so that white light is emitted by light emitted from each of the light-emitting layer 120a and the light-emitting layer 120b.

  The light-emitting layer 120 may have a structure in which three or more layers are stacked, and may include a layer that does not have a light-emitting material.

<3. Configuration Example 3 of Light-Emitting Element>
Next, structural examples different from the light-emitting elements illustrated in FIGS. 1A and 1B and FIGS. 2A and 2B are described below with reference to FIGS.

  3A and 3B are cross-sectional views illustrating a light-emitting element of one embodiment of the present invention. 3 (A) and 3 (B), the same hatch pattern is used for portions having the same functions as those shown in FIGS. 1 (A) and 1 (B) and FIGS. 2 (A) and 2 (B). May be omitted. Moreover, the same code | symbol is attached | subjected to the location which has the same function, and the detailed description may be abbreviate | omitted.

  FIGS. 3A and 3B are structural examples of a light-emitting element having an oxide layer 101 d below the electrode layer 101. A light-emitting element 174 illustrated in FIG. 3A is a light-emitting element having an oxide layer 101d under a conductive layer 101a as part of the structure of the electrode layer 101. In other words, this is a configuration example of the electrode layer 101 in which the conductive layer 101a is sandwiched between the oxide layer 101b and the oxide layer 101d. A light-emitting element 176 illustrated in FIG. 3B is a light-emitting element including an oxide layer 101d and a transparent conductive film 101e below the conductive layer 101a as part of the structure of the electrode layer 101. In other words, this is a configuration example of the electrode layer 101 in which the conductive layer 101a is sandwiched between the oxide layer 101b and the oxide layer 101d and is further sandwiched between the transparent conductive film 101c and the transparent conductive film 101e.

  Different materials may be used for the oxide layer 101d and the oxide layer 101b, or the same material may be used. In the case where the same material is used, the conductive layer 101a has a structure in which it is sandwiched between the same oxide materials. When the structure of one embodiment of the present invention is used for the oxide layer 101d and the oxide layer 101b, the conductive layer 101a is sandwiched between stable oxide layers. Therefore, the stable electrode layer 101 can be manufactured. In addition, it is preferable that the conductive layer 101a be sandwiched between the same oxide materials because a pattern can be easily formed by an etching process.

  Different materials may be used for the transparent conductive film 101e and the transparent conductive film 101c, or the same material may be used. When the same material is used, the conductive layer 101a and the oxide layers 101b and 101d have a structure that is sandwiched between the same transparent conductive material. It is preferable that the electrode layer 101 be sandwiched between the same transparent conductive film materials because pattern formation by an etching process becomes easy.

  Note that the light-emitting element 176 may have only one of the transparent conductive film 101c and the transparent conductive film 101e. Alternatively, only one of the oxide layer 101d and the transparent conductive film 101e may be used.

<4. Configuration Example 4 of Light-Emitting Element>
Next, a structural example different from the light-emitting element illustrated in FIGS. 1 to 3 is described below with reference to FIGS.

  FIG. 4 is a cross-sectional view illustrating a light-emitting element of one embodiment of the present invention. In FIG. 4, portions having the same functions as those shown in FIGS. 1 to 3 have the same hatch pattern, and the symbols may be omitted. Moreover, the same code | symbol is attached | subjected to the location which has the same function, and the detailed description may be abbreviate | omitted.

  FIG. 4 is a configuration example of a tandem light-emitting element in which a plurality of light-emitting units are stacked via a charge generation layer between a pair of electrode layers. The tandem light-emitting element 190 is a light-emitting element including a light-emitting unit 106, a charge generation layer 115, and a light-emitting unit 108 between the electrode layer 101 and the electrode layer 102. The light emitting unit 106 includes a hole injection layer 111, a hole transport layer 112, a light emitting layer 121, an electron transport layer 113, and an electron injection layer 114. The light emitting unit 108 includes a hole injection layer. The structure includes a layer 116, a hole transport layer 117, a light emitting layer 122, an electron transport layer 118, and an electron injection layer 119. That is, the tandem light-emitting element 190 is a light-emitting element having a plurality of light-emitting units, and the light-emitting elements shown in FIGS. 1 to 3 each have one light-emitting unit.

  The light-emitting layer 121 and the light-emitting layer 122 can have a structure in which two layers are stacked, such as the light-emitting layer 122a and the light-emitting layer 122b. By using two types of light-emitting materials having a function of exhibiting different colors, ie, a first compound and a second compound, in the two light-emitting layers, light emission having a plurality of light emission colors can be obtained simultaneously. In particular, it is preferable to select a light-emitting material to be used for each light-emitting layer so that the light-emitting layer 121 and the light-emitting layer 122 emit white light.

  The light-emitting layer 121 or the light-emitting layer 122 may have a structure in which three or more layers are stacked, or may include a layer that does not have a light-emitting material.

<5. Configuration Example 5 of Light-Emitting Element>
Next, structural examples different from the light-emitting elements illustrated in FIGS. 1 to 4 are described below with reference to FIGS.

  5A and 5B are cross-sectional views illustrating a light-emitting element of one embodiment of the present invention. 5A and 5B, portions having functions similar to those shown in FIGS. 1 to 4 may have the same hatch pattern and may be omitted. Moreover, the same code | symbol is attached | subjected to the location which has the same function, and the detailed description may be abbreviate | omitted.

  5A and 5B illustrate configuration examples of the light-emitting element 250 and the light-emitting element 270 which have different structures from the light-emitting elements illustrated in FIGS. A light-emitting element 250 illustrated in FIG. 5A includes an electrode layer 101, an electrode layer 102, and an electrode layer 103 over a substrate 200. The electrode layer 101 includes a conductive layer 101a and an oxide layer 101b in contact with the conductive layer 101a. The electrode layer 103 includes a conductive layer 103a, an oxide layer 103b in contact with the conductive layer 103a, and a transparent conductive film 103c over the oxide layer 103b.

  The light-emitting element 250 includes a hole injection layer 111, a hole transport layer 112, a light-emitting layer 120, an electron transport layer 118, and an electron injection layer 119 between the electrode layer 101 and the electrode layer 102. And having. The light-emitting element 250 includes a hole injection layer 111, a hole transport layer 112, a light-emitting layer 120, an electron transport layer 118, and an electron injection layer 119 between the electrode layer 102 and the electrode layer 103. And having.

  In FIG. 5A, the hole injection layer 111 sandwiched between the electrode layer 101 and the electrode layer 102 in the region 210A and sandwiched between the electrode layer 102 and the electrode layer 103 in the region 210B, and the hole transport Each functional layer exemplified by the layer 112, the light emitting layer 120, the electron transport layer 118, and the electron injection layer 119 is illustrated in a separated state, but each functional layer is divided into the region 210A and the region 210A. A common film can be formed without separation in the region 210B.

  The light emitting layer 120 can have a structure in which a light emitting layer 120a and a light emitting layer 120b are stacked. By using two types of light-emitting materials having a function of exhibiting different colors, ie, a first compound and a second compound, in the two light-emitting layers, light emission having a plurality of light emission colors can be obtained simultaneously. In particular, it is preferable to select a light-emitting material used for each light-emitting layer so that the light-emitting layer 120a and the light-emitting layer 120b emit white light.

  In addition, each of the light emitting layers 120 may have a structure in which three or more layers are stacked, and may include a layer that does not have a light emitting material.

  In the case where the oxide layer 101b included in the electrode layer 101 and the oxide layer 103b included in the electrode layer 103 are formed using different materials, the electrode layer 101 and the electrode layer 103 each have electrons or EL to the EL layer. The hole injectability is different.

  In the case where the electrode layer 101 and the electrode layer 103 are used as an anode, the oxide layer 101b and the oxide layer 103b are preferably formed using a material with a high work function. Among these, for example, when a material having a relatively low work function and a low hole injecting property is used for the oxide layer 101b, holes injected from the anode to the EL layer and electrons injected from the cathode to the EL layer The region where the recombination occurs is relatively densely distributed on the anode side. On the other hand, when a material having a relatively high work function and a high hole injecting property is used for the oxide layer 103b, a region where holes and electrons recombine is relatively densely distributed on the cathode side.

  In addition, when the light emitting layer 120 is present in a region where holes and electrons are recombined (recombination region), light is emitted from the light emitting layer 120. By adjusting the material and thickness of each layer forming the light-emitting element 250 so that the carrier recombination region is dense in the light-emitting layer 120, the light emission intensity of the light-emitting element 250 can be improved and the light emission efficiency can be increased. . If the light-emitting layer 120 is a single layer, the shape of the spectrum of light emitted from the light-emitting material (the relative intensity ratio of each wavelength component) is not affected by the region where holes and electrons recombine. Even if it changes, the luminescent color of the luminescent material itself does not change.

  On the other hand, as shown in FIGS. 5A and 5B, when the light-emitting layer 120 is composed of a plurality of layers (the light-emitting layer 120a and the light-emitting layer 120b), the hole or electron injection property changes, and the inside of the light-emitting layer 120 When the region in which holes and electrons recombine in (the recombination region) changes, the ratio of the intensity of light exhibited by the light emitting layer 120a and the light emitting layer 120b changes. Accordingly, when the light colors presented by the light emitting layer 120a and the light emitting layer 120b are different, the shape of the spectrum of light extracted as the entire light emitting element 250 (the relative intensity ratio of each wavelength component) changes, that is, the light emitting element. The color of light that 250 exhibits changes.

  Therefore, in the light-emitting element according to one embodiment of the present invention, the oxide layer 101b included in the electrode layer 101 includes In and a stabilizer M (M is Al, Si, Ti, Ga, Y, Zr, Sn, La, Ce). , Nd or Hf), and the stabilizer M content is preferably equal to or higher than the In content. The oxide layer 103b included in the electrode layer 103 is different from the oxide layer 101b in oxidation. It is preferable to have a thing. In addition, the structure in which the light-emitting layer 120 includes at least two light-emitting materials having a function of exhibiting different emission colors makes it possible to emit light from the region 210A sandwiched between the electrode layer 101 and the electrode layer 102, 102 and the electrode layer 103, which is preferable because the emitted light can be different from the light emitted from the region 210B sandwiched between the electrode 102 and the electrode layer 103. That is, even if the region 210A and the region 210B have the light emitting layer 120 in common, the configuration of the electrode layer 101 and the configuration of the electrode layer 103 are different from each other, so that the region 210A and the region 210B are extracted from the region 210A and the region 210B. The emission colors of emitted light can be made different from each other.

  Note that the same material may be used for the oxide layer 101b and the oxide layer 103b. In addition, by using the same material for the oxide layer 101b and the oxide layer 103b and using different deposition processes, electrons or holes can be injected from the electrode layer 101 or the electrode layer 103 to the EL layer. May be changed. For example, the pressure in the deposition chamber when forming the oxide layer 101b or the oxide layer 103b, a deposition gas (for example, oxygen, argon, or a mixed gas containing oxygen), deposition energy, and temperature during deposition By changing the distance between the target and the substrate, or the temperature and surface treatment after film formation, etc., the oxide layer has different properties, so that electrons or holes from the oxide layer to the EL layer can be obtained. The injectability of may be changed. In addition, the oxide layer 101b and the oxide layer 103b have the same element, and the content or content of the elements is different from each other, whereby the oxide layer 101b and the oxide layer 103b are Different materials may be used.

  Further, the same material may be used for the conductive layer 101a and the conductive layer 103a, or different materials may be used. When the same material is used for the conductive layer 101a and the conductive layer 103a, the manufacturing cost of the light-emitting element 250 can be reduced.

  In the light-emitting element 250 described in this embodiment, the same structure can be used for the EL layers included in the regions 210A and 210B. Therefore, for example, by using the light-emitting element 250 having the regions 210A and 210B that exhibit different emission colors as the sub-pixels in the pixel of the display device, different emission colors from each sub-pixel without separately coating the EL layer. The light can be taken out. Therefore, a display device with high light use efficiency can be manufactured with high yield. That is, the display device including the light-emitting element 250 can reduce power consumption. In addition, the display device including the light-emitting element 250 can reduce manufacturing costs. In addition, since there is no layout restriction due to a margin (margin) required for separate application to the EL layer, a display device with a high degree of layout freedom and easy to manufacture can be manufactured. In addition, a display device having high resolution can be manufactured.

  Further, as in the light-emitting element 270 illustrated in FIG. 5B, the electrode layer 101 includes a conductive layer 101a having a function of reflecting light, an oxide layer 101b in contact with the conductive layer 101a, and an oxide layer 101b. The upper transparent conductive film 101c may be included.

  By including the transparent conductive film 101c, the electrode layer 101 can be an electrode with favorable carrier injection properties to the EL layer.

  Note that the same material may be used for the transparent conductive film 101c and the transparent conductive film 103c, or different materials may be used. When the same material is used for the transparent conductive film 101c and the transparent conductive film 103c, the manufacturing cost of the light-emitting element 270 can be reduced. Even in that case, the oxide layer 101b and the oxide layer 103b have different configurations, so that the electrode layer 101 and the electrode layer 103 have different electrode configurations in which electrons or holes can be injected into the EL layer. can do.

  In the case where different materials are used for the transparent conductive film 101c and the transparent conductive film 103c, the electrode layer 101 and the electrode layer 103 have different electron or hole injection properties into the EL layer. That is, in the light-emitting element 270 illustrated in FIG. 5B, an electron or positive current is generated between the region 211A sandwiched between the electrode layer 101 and the electrode layer 102 and the region 211B sandwiched between the electrode layer 102 and the electrode layer 103. Since the hole injecting property is different, the distance from the electrode layer 102 of the electron-hole recombination region is different between the region 211A and the region 211B.

  Accordingly, the emission color of light emitted from the region 211A and the emission color of light emission from the region 211B are different from each other. That is, by making the configuration of the electrode layer 101 and the configuration of the electrode layer 103 different, the emission colors of light emitted from the region 211A and the region 211B can be different from each other.

<6. Configuration Example 6 of Light-Emitting Element>
Next, structural examples different from the light-emitting elements illustrated in FIGS. 1 to 5 are described below with reference to FIGS.

  6A and 6B are cross-sectional views illustrating a light-emitting element of one embodiment of the present invention. 6A and 6B, portions having the same functions as the reference numerals shown in FIGS. 1 to 5 have the same hatch pattern, and the reference numerals may be omitted. Moreover, the same code | symbol is attached | subjected to the location which has the same function, and the detailed description may be abbreviate | omitted.

  6A and 6B are configuration examples of a tandem light-emitting element in which a plurality of light-emitting units are stacked with a charge generation layer 115 interposed between a pair of electrode layers. The light-emitting element 280 and the light-emitting element 282 include the electrode layer 101, the electrode layer 102, and the electrode layer 103 over the substrate 200. Further, the light-emitting layer 121, the charge generation layer 115, and the light-emitting layer 122 are provided between the electrode layer 101 and the electrode layer 102 and between the electrode layer 102 and the electrode layer 103. In addition, the hole injection layer 111, the hole transport layer 112, the electron transport layer 113, the electron injection layer 114, the hole injection layer 116, the hole transport layer 117, the electron transport layer 118, and the electron injection A layer 119.

  In FIG. 6A, the hole injection layer 111 sandwiched between the electrode layer 101 and the electrode layer 102 in the region 212A and sandwiched between the electrode layer 102 and the electrode layer 103 in the region 212B, and hole transport Layer 112, light emitting layer 121, electron transport layer 113, electron injection layer 114, charge generation layer 115, hole injection layer 116, hole transport layer 117, light emitting layer 122, and electron transport layer 118. And the electron injection layer 119 are illustrated as being separated from each other, but each functional layer is formed in common without being separated in the region 212A and the region 212B. Can do.

  The electrode layer 101 in the light-emitting element 280 illustrated in FIG. 6A includes a conductive layer 101a and an oxide layer 101b in contact with the conductive layer 101a. The electrode layer 103 includes a conductive layer 103a, an oxide layer 103b in contact with the conductive layer 103a, and a transparent conductive film 103c over the oxide layer 103b.

  The electrode layer 101 in the light-emitting element 282 illustrated in FIG. 6B includes a conductive layer 101a, an oxide layer 101b in contact with the conductive layer 101a, and a transparent conductive film 101c over the oxide layer 101b. The electrode layer 103 includes a conductive layer 103a, an oxide layer 103b in contact with the conductive layer 103a, and a transparent conductive film 103c over the oxide layer 103b.

  The light-emitting layer 121 and the light-emitting layer 122 can have a structure in which two layers are stacked, such as the light-emitting layer 121a and the light-emitting layer 121b. By using two kinds of light emitting materials having a function of exhibiting different colors, ie, a first compound and a second compound, in the two light emitting layers, light emission having a plurality of light emission colors can be obtained simultaneously. In particular, it is preferable to select a light-emitting material to be used for each light-emitting layer so that the light-emitting layer 121 and the light-emitting layer 122 emit white light.

  The light-emitting layer 121 or the light-emitting layer 122 may have a structure in which three or more layers are stacked, or may include a layer that does not have a light-emitting material.

  In the case where the oxide layer 101b included in the electrode layer 101 and the oxide layer 103b included in the electrode layer 103 are formed using different materials, the electrode layer 101 and the electrode layer 103 each have electrons or EL to the EL layer. The hole injectability is different. That is, in the light-emitting element 280, the region 212A sandwiched between the electrode layer 101 and the electrode layer 102 and the region 212B sandwiched between the electrode layer 102 and the electrode layer 103 have different electron or hole injection properties. In the region 212A and the region 212B, the distance from the electrode layer 102 in the region where the electrons and holes are recombined (recombination region) is different.

  Therefore, in the light-emitting element 280, the emission color emitted from the region 212A and the emission color emitted from the region 212B are different from each other. In the light-emitting element 282, the emission color emitted from the region 213A is different from the emission color emitted from the region 213B. For that purpose, the oxide layer 101b constituting the electrode layer 101 includes In, a stabilizer M (M represents Al, Si, Ti, Ga, Y, Zr, Sn, La, Ce, Nd, or Hf), The content of the stabilizer M is preferably equal to or higher than the content of In, and the oxide layer 103b included in the electrode layer 103 preferably includes an oxide different from that of the oxide layer 101b. That is, by making the configuration of the electrode layer 101 and the configuration of the electrode layer 103 different, the emission color of light emitted from the region 212A and the region 212B in the light-emitting element 280 is changed to a different emission color. Can do. Similarly, in the light-emitting element 282, the emission colors of light emitted from the region 213A and the region 213B can be different from each other.

  Note that in the light-emitting element 280 and the light-emitting element 282, the same material may be used for the oxide layer 101b and the oxide layer 103b. In addition, by using the same material for the oxide layer 101b and the oxide layer 103b and using different deposition processes, electrons or holes can be injected from the electrode layer 101 or the electrode layer 103 to the EL layer. May be changed. For example, the pressure in the deposition chamber when forming the oxide layer 101b or the oxide layer 103b, a deposition gas (for example, oxygen, argon, or a mixed gas containing oxygen), deposition energy, and temperature during deposition By changing the distance between the target and the substrate, or the temperature and surface treatment after film formation, etc., the oxide layer has different properties, so that electrons or holes from the oxide layer to the EL layer can be obtained. The injectability of may be changed. In addition, the oxide layer 101b and the oxide layer 103b have the same element, and the oxide layer 101b and the oxide layer 103b are made of different materials by changing the content or content of the elements. It is good.

  A light emitting element 280 having a region 212A and a region 212B that emit light of different emission colors or a light emitting element 282 having a region 213A and a region 213B of light having different emission colors is used as a sub-pixel in the pixel of the display device. By using it, light of different emission colors can be extracted from each sub-pixel without separately coating the EL layer. Therefore, a display device with high light use efficiency and easy manufacturing can be manufactured. That is, a display device including the light-emitting element 280 or the light-emitting element 282 can reduce power consumption. Further, the display device including the light-emitting element 280 or the light-emitting element 282 can reduce manufacturing costs.

<7. Configuration Example 7 of Light-Emitting Element>
Next, structural examples different from those of the light-emitting elements illustrated in FIGS. 1 to 6 are described below with reference to FIGS.

  7A and 7B are cross-sectional views illustrating a light-emitting element of one embodiment of the present invention. In FIGS. 7A and 7B, portions having the same functions as those shown in FIGS. 1 to 6 have the same hatch pattern and may be omitted. Moreover, the same code | symbol is attached | subjected to the location which has the same function, and the detailed description may be abbreviate | omitted.

  7A and 7B are configuration examples of a tandem light-emitting element in which a plurality of light-emitting units are stacked with a charge generation layer 115 interposed between a pair of electrode layers. A light-emitting element 290 illustrated in FIG. 7A is a top emission type light-emitting element that extracts light in a direction opposite to the substrate 200, and a light-emitting element 292 illustrated in FIG. This is a bottom emission type light emitting device for taking out the light. Note that one embodiment of the present invention is not limited to this, and a dual emission type in which light emitted from a light-emitting element is extracted both above and below the substrate 200 over which the light-emitting element is formed may be used.

  The light-emitting element 290 and the light-emitting element 292 include the electrode layer 101, the electrode layer 102, the electrode layer 103, and the electrode layer 104 over the substrate 200. In addition, the light emitting layer 121, the charge generation layer 115, and the light emission are provided between the electrode layer 101 and the electrode layer 102, between the electrode layer 102 and the electrode layer 103, and between the electrode layer 102 and the electrode layer 104. A layer 122. In addition, the hole injection layer 111, the hole transport layer 112, the electron transport layer 113, the electron injection layer 114, the hole injection layer 116, the hole transport layer 117, the electron transport layer 118, and the electron injection A layer 119.

  The electrode layer 101 includes a conductive layer 101a, an oxide layer 101b in contact with the conductive layer 101a, and a transparent conductive film 101c over the oxide layer 101b. The electrode layer 103 includes a conductive layer 103a, an oxide layer 103b in contact with the conductive layer 103a, and a transparent conductive film 103c over the oxide layer 103b. The electrode layer 104 includes a conductive layer 104a and an oxide layer 104b in contact with the conductive layer 104a.

  A light-emitting element 290 illustrated in FIG. 7A and a light-emitting element 292 illustrated in FIG. 7B are sandwiched between a region 221R sandwiched between the electrode layer 101 and the electrode layer 102, and the electrode layer 102 and the electrode layer 103. A partition wall 140 is provided between the region 221 </ b> G and the region 221 </ b> B sandwiched between the electrode layer 102 and the electrode layer 104. The partition 140 has an insulating property. The partition 140 covers the end portions of the electrode layer 101, the electrode layer 103, and the electrode layer 104, and has an opening overlapping with the electrode layer. By providing the partition wall 140, the electrode layers over the substrate 200 can be separated into island shapes like the electrode layer 101, the electrode layer 103, and the electrode layer 104, respectively.

  In addition, the light-emitting element 290 and the light-emitting element 292 include an optical element 224R, an optical element 224G, and an optical element 224B, respectively, in the direction in which light emitted from the region 221R, the region 221G, and the region 221B is extracted. Light presented from each region is emitted to the outside of the light emitting element through each optical element. That is, light presented from the region 221R is emitted through the optical element 224R, light presented from the region 221G is emitted through the optical element 224G, and light presented from the region 221B is emitted from the optical element 224B. Is injected through.

  Further, the optical element 224R, the optical element 224G, and the optical element 224B have a function of selectively transmitting light of a specific color from incident light. For example, light presented from the region 221R emitted through the optical element 224R becomes red light, and light presented from the region 221G emitted through the optical element 224G becomes green light. The light presented from the region 221B emitted through the optical element 224B is blue light.

  7A and 7B, the light emitted from each region through each optical element is light that exhibits red (R), light that exhibits green (G), and light that exhibits blue (B). , As schematically shown by broken arrows. However, the color of light emitted from each region is not limited to these.

  Further, a light shielding layer 223 is provided between the optical elements. The light shielding layer 223 has a function of shielding light emitted from adjacent regions. Note that the light-blocking layer 223 may not be provided.

  Further, the light-emitting element 290 and the light-emitting element 292 have a microcavity structure.

≪Microcavity structure≫
Light emitted from the light-emitting layer 121 and the light-emitting layer 122 is resonated between a pair of electrode layers (for example, the electrode layer 101 and the electrode layer 102). In the light-emitting element 290 and the light-emitting element 292, the wavelength of light emitted from the light-emitting layer 121 and the light-emitting layer 122 can be increased by adjusting the thickness of the oxide layer and the transparent conductive film in each region. Note that the wavelength of light emitted from the light-emitting layer 121 and the light-emitting layer 122 may be increased by changing the thickness of at least one of the hole injection layer 111 and the hole transport layer 112 in each region.

For example, when the refractive index of a substance having a reflecting function in the electrode layer 101, the electrode layer 102, the electrode layer 103, and the electrode layer 104 is smaller than the refractive index of the light-emitting layer 121 or the light-emitting layer 122, the electrode layer 101 The thickness of the oxide layer 101b and the transparent conductive film 101c included in the optical layer is such that the optical distance between the electrode layer 101 and the electrode layer 102 is m _R λ _R / 2 (m _R is a natural number, and λ _R is a light that enhances in the region 221R. Are adjusted so that the respective wavelengths are expressed). Similarly, the film thicknesses of the oxide layer 103b and the transparent conductive film 103c included in the electrode layer 103 are set such that the optical distance between the electrode layer 103 and the electrode layer 102 is m _G λ _G / 2 (m _G is a natural number, λ _G Represents the wavelength of light intensified in the region 221G. Further, the thickness of the oxide layer 104b included in the electrode layer 104 is set such that the optical distance between the electrode layer 104 and the electrode layer 102 is m _B λ _B / 2 (m _B is a natural number, and λ _B is light that is enhanced in the region 221B Are adjusted so that the respective wavelengths are expressed).

  As described above, by providing a microcavity structure and adjusting the optical distance between the electrode layers in each region, light scattering and light absorption in the vicinity of each electrode layer can be suppressed, and high light extraction efficiency can be realized. it can.

  Note that the light-emitting element 290 illustrated in FIG. 7A is a top emission light-emitting element; thus, the conductive layer 101a included in the electrode layer 101, the conductive layer 103a included in the electrode layer 103, and the conductive layer included in the electrode layer 104 are used. 104a preferably has a function of reflecting light. The electrode layer 102 preferably has a function of transmitting light and a function of reflecting light.

  7B is a bottom emission light-emitting element, the conductive layer 101a included in the electrode layer 101, the conductive layer 103a included in the electrode layer 103, and the conductive layer 104a included in the electrode layer 104. It is preferable to have a function of reflecting light and a function of transmitting light. The electrode layer 102 preferably has a function of reflecting light.

  The light-emitting layer 121 and the light-emitting layer 122 can have a structure in which two layers are stacked, such as the light-emitting layer 121a and the light-emitting layer 121b. By using two types of light-emitting materials having a function of exhibiting different colors, which are the first compound and the second compound, in the two light-emitting layers, light emission having a plurality of light emission colors can be obtained simultaneously. In particular, it is preferable to select a light-emitting material used for each light-emitting layer so that the light-emitting layers 121 and 122 emit white light.

  The light-emitting layer 121 or the light-emitting layer 122 may have a structure in which three or more layers are stacked, or may include a layer that does not have a light-emitting material.

  The oxide layer 101b constituting the electrode layer 101 includes In and a stabilizer M (M represents Al, Si, Ti, Ga, Y, Zr, Sn, La, Ce, Nd, or Hf), When the content of the stabilizer M included in the oxide layer 101b is equal to or greater than the content of In, and the oxide layer 103b included in the electrode layer 103 includes an oxide different from the oxide layer 101b, The electrode layer 103 has different electron or hole injection properties into the EL layer. That is, in the light-emitting element 290 and the light-emitting element 292, injection of electrons or holes is performed between the region 221R sandwiched between the electrode layer 101 and the electrode layer 102 and the region 221G sandwiched between the electrode layer 102 and the electrode layer 103. Therefore, the region 221 </ b> R and the region 221 </ b> G have different distances from the electrode layer 102 in the region where electrons and holes are recombined.

  In addition, when the configuration of the electrode layer 103 and the configuration of the electrode layer 104 are different, the electrode layer 103 and the electrode layer 104 have different electron or hole injection properties into the EL layer, respectively. . For example, in the case where the electrode layer 103 includes the oxide layer 103b and the transparent conductive film 103c and the electrode layer 104 includes the oxide layer 104b, in the light-emitting element 290 and the light-emitting element 292, the electrode layer 103 and the electrode layer 102 are included. The region 221G and the region 221B sandwiched between the electrode layer 104 and the electrode layer 102 have different electron or hole injection properties, so that the region 221G and the region 221B have electrons and holes. The distances from the electrode layer 102 in the recombination region are different.

  Furthermore, by adjusting the optical distance of the region 221R, the optical distance of the region 221G, and the optical distance of the region 221B in the microcavity structure described above to be different from each other, the emission color of light emitted from the region 221R The emission color emitted from the region 221G and the emission color emitted from the region 221B are different from each other. That is, the structure of the electrode layer 101, the structure of the electrode layer 103, and the structure of the electrode layer 104 are different from each other, whereby the region 221R, the region 221G, and the region in the light-emitting element 290 and the light-emitting element 292 are provided. The emission colors from 221B can be different from each other.

  Note that in the light-emitting element 290 and the light-emitting element 292, the same material may be used for the oxide layer 101b, the oxide layer 103b, and the oxide layer 104b. In addition, by using the same material for the oxide layer 101b, the oxide layer 103b, and the oxide layer 104b and using different deposition processes, the electrode layer 101, the electrode layer 103, or the electrode layer 104 can be transferred to the EL layer. The injection property of electrons or holes may be changed. For example, the pressure in the deposition chamber when forming the oxide layer 101b, the oxide layer 103b, or the oxide layer 104b, a deposition gas (for example, oxygen, argon, or a mixed gas containing oxygen), and deposition energy By changing the temperature at the time of film formation, the distance between the target and the substrate, or the temperature and surface treatment after the film formation, etc., and changing the properties of the oxide layer, the oxide layer can be changed to the EL layer. You may change the injection | pouring property of the electron or the hole to. In addition, the oxide layer 101b, the oxide layer 103b, and the oxide layer 104b have the same element, and the content or content of the elements is different from each other, whereby the oxide layer 101b, the oxide layer 103b, And the oxide layer 104b may be different from each other.

  In the light-emitting element 290 and the light-emitting element 292, the same material may be used for the conductive layer 101a, the conductive layer 103a, or the conductive layer 104a, or different materials may be used. In the case where the same material is used for the conductive layer 101a, the conductive layer 103a, and the conductive layer 104a, manufacturing costs of the light-emitting element 290 and the light-emitting element 292 can be reduced.

  In the light-emitting element 290 and the light-emitting element 292, the same material may be used for the transparent conductive film 101c and the transparent conductive film 103c, or different materials may be used. In the case where the same material is used for the transparent conductive film 101c and the transparent conductive film 103c, manufacturing costs of the light-emitting element 290 and the light-emitting element 292 can be reduced. Even in that case, the oxide layer 101b and the oxide layer 103b have different configurations, so that the electrode layer 101 and the electrode layer 103 have different electrode configurations in which electrons or holes can be injected into the EL layer. can do.

  In the case where different materials are used for the transparent conductive film 101c and the transparent conductive film 103c, the electrode layer 101 and the electrode layer 103 have different electron or hole injection properties into the EL layer. That is, since the region 221R sandwiched between the electrode layer 101 and the electrode layer 102 and the region 221G sandwiched between the electrode layer 102 and the electrode layer 103 have different electron or hole injection properties, the region 221R and The distance between the region 221G and the region where the electrons and holes are recombined from the electrode layer 102 is different, and light emitted from the region 221R and the region 221G has different emission colors.

  As described above, the configuration of the electrode layer 101, the configuration of the electrode layer 103, and the configuration of the electrode layer 104 are different from each other, so that the emission color of light emitted from the region 221R and the region 221G are displayed. The emission color of emitted light and the emission color of light emitted from the region 221B can be different from each other. That is, the emission colors from the region 221R, the region 221G, and the region 221B can be different from each other.

  Of the electrode layer 101, the electrode layer 103, and the electrode layer 104, the configuration of at least one electrode layer may be different from the configuration of the other electrode layers, and all the three electrode layers have different configurations. There is no need. For example, the electrode layer 103 and the electrode layer 104 may have the same configuration and may be different from the configuration of the electrode layer 101.

  As described above, by using the light-emitting element 290 or the light-emitting element 292 including the region 221R, the region 221G, and the region 221B that exhibit different emission colors as the pixels of the display device, each EL layer can be formed without being separately applied. Different emission colors can be extracted from the sub-pixels. Therefore, a display device with high light use efficiency and easy manufacturing can be manufactured. That is, a display device including the light-emitting element 290 or the light-emitting element 292 can reduce power consumption. In addition, a display device including the light-emitting element 290 or the light-emitting element 292 can reduce manufacturing costs.

<8. Components of light emitting element>
Next, details of the components of the light-emitting element shown in FIGS. 1 to 7 will be described below.

<< Board >>
As the substrate over which the light-emitting element according to one embodiment of the present invention can be formed, glass, quartz, plastic, or the like can be used, for example. A flexible substrate may be used. The flexible substrate is a substrate that can be bent (flexible), and examples thereof include a plastic substrate made of polycarbonate or polyarylate. Moreover, a film, an inorganic vapor deposition film, etc. can also be used. Note that other materials may be used as long as they function as a support in the manufacturing process of the light-emitting element and the display device. Or what is necessary is just to have a function which protects a light emitting element and an optical element.

  For example, in this specification and the like, a light-emitting element or a transistor can be formed using various substrates. The kind of board | substrate is not limited to a specific thing. Examples of the substrate include a semiconductor substrate (for example, a single crystal substrate or a silicon substrate), an SOI substrate, a glass substrate, a quartz substrate, a plastic substrate, a metal substrate, a stainless steel substrate, a substrate having stainless steel foil, and a tungsten substrate. , A substrate having a tungsten foil, a flexible substrate, a laminated film, a paper containing a fibrous material, or a base film. Examples of the glass substrate include barium borosilicate glass, aluminoborosilicate glass, and soda lime glass. Examples of the flexible substrate, the laminated film, and the base film include the following. For example, there are plastics represented by polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyether sulfone (PES), and polytetrafluoroethylene (PTFE). Another example is a resin such as acrylic. Alternatively, examples include polypropylene, polyester, polyvinyl fluoride, and polyvinyl chloride. As an example, there are polyamide, polyimide, aramid, epoxy, an inorganic vapor deposition film, papers, and the like. In particular, by manufacturing a transistor using a semiconductor substrate, a single crystal substrate, an SOI substrate, or the like, a transistor with small variation in characteristics, size, or shape, high current capability, and small size can be manufactured. . When a circuit is formed using such transistors, the power consumption of the circuit can be reduced or the circuit can be highly integrated.

  Alternatively, a flexible substrate may be used as a substrate, and a light-emitting element or a transistor may be formed directly over the flexible substrate. Alternatively, a separation layer may be provided between the substrate and the transistor or between the substrate and the light-emitting element. The separation layer can be used to separate a part of the display device from the substrate and transfer it to another substrate after the display device is partially or entirely completed thereon. At that time, the light-emitting element and the transistor can be transferred to a substrate having poor heat resistance or a flexible substrate. Note that, for example, a structure of a laminated structure of an inorganic film of a tungsten film and a silicon oxide film or a structure in which a resin film such as polyimide is formed over a substrate can be used for the above-described release layer.

  That is, a light-emitting element or a transistor may be formed using a certain substrate, and then the light-emitting element or the transistor may be transferred to another substrate, and the light-emitting element or the transistor may be disposed on another substrate. As an example of a substrate on which a light emitting element or a transistor is transferred, in addition to the substrate on which the above light emitting element or transistor can be formed, a cellophane substrate, a stone substrate, a wood substrate, a cloth substrate (natural fiber (silk, cotton, hemp), There are synthetic fibers (nylon, polyurethane, polyester) or recycled fibers (including acetate, cupra, rayon, recycled polyester), leather substrates, rubber substrates, and the like. By using these substrates, it is possible to form a transistor with good characteristics, a transistor with low power consumption, manufacture a display device that is not easily broken, impart heat resistance, reduce weight, or thin.

≪A pair of electrodes≫
The electrode layer 101 and the electrode layer 103 have a function as an anode or a cathode of each light emitting element. Note that the conductive layer 101a included in the electrode layer 101 and the conductive layer 103a included in the electrode layer 103 are preferably formed using a conductive material having a function of reflecting light. Examples of the conductive material include Al or an alloy containing Al. Examples of the alloy containing Al include an alloy containing Al and L (L represents one or more of Ti, Nd, nickel (Ni), and La). Aluminum has a low resistance value and a high light reflectance. In addition, since aluminum is abundant in the crust and inexpensive, manufacturing cost of a light-emitting element by using aluminum can be reduced. Also, Ag or Ag and N (N is Y, Nd, Mg, Al, Ti, Ga, Zn, In, tungsten (W), manganese (Mn), Sn, iron (Fe), Ni, copper (Cu ), Palladium (Pd), iridium (Ir), or gold (Au)) may be used. Examples of the alloy containing silver include an alloy containing silver, palladium and copper, an alloy containing silver and copper, an alloy containing silver and magnesium, an alloy containing silver and nickel, and an alloy containing silver and gold. Note that in the case where light is extracted from the electrode layer 101 and the electrode layer 103, the conductive layer 101a and the conductive layer 103a are exemplified as the conductive material with a thickness that allows light to pass therethrough (preferably, about 5 nm to 30 nm). It is preferably formed of a metal thin film, and preferably has a function of reflecting light and a function of transmitting light.

  Further, as already described, the oxide layer 101b constituting the electrode layer 101 includes In and a stabilizer M (M is Al, Si, Ti, Ga, Y, Zr, Sn, La, Ce, Nd, or Hf). It is preferably formed of an oxide material having By doing so, transfer of electrons or transfer of oxygen between the oxide layer 101b and the conductive layer 101a can be suppressed. Therefore, the occurrence of electrolytic corrosion in the electrode layer 101 can be prevented, and the driving voltage of the light emitting element can be reduced. In addition, since the content of the stabilizer M included in the oxide layer 101b is greater than or equal to the content of In, oxygen exchange between the oxide layer 101b and the conductive layer 101a can be effectively prevented. Is preferred.

  Examples of other stabilizers M include praseodymium (Pr), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium, which are lanthanoids. (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), etc.

  The oxide layer 101b may contain metal elements other than In and the stabilizer M. In particular, a material containing zinc (Zn) or zinc oxide is preferable because a uniform film can be formed. In other words, the oxide layer 101b is preferably formed using an oxide containing In, a stabilizer M, and Zn.

  Examples of oxides included in the oxide layer 101b include In—Ga—Zn-based oxides, In—Al—Zn-based oxides, In—Si—Zn-based oxides, In—Ti—Zn-based oxides, In -Ti-Y oxide, In-Zr-Zn oxide, In-Sn-Zn oxide, In-La-Zn oxide, In-Ce-Zn oxide, In-Nd-Zn oxide Oxide, In-Hf-Zn-based oxide, In-Pr-Zn-based oxide, In-Sm-Zn-based oxide, In-Eu-Zn-based oxide, In-Gd-Zn-based oxide, In- Tb-Zn oxide, In-Dy-Zn oxide, In-Ho-Zn oxide, In-Er-Zn oxide, In-Tm-Zn oxide, In-Yb-Zn oxide , In-Lu-Zn-based oxide, In-Sn-Ga-Zn-based oxide, In-Hf-Ga Zn-based oxide, In-Al-Ga-Zn-based oxide, In-Sn-Al-Zn-based oxide, In-Sn-Hf-Zn-based oxide, In-Hf-Al-Zn-based oxide, Can be used.

  In the case where the oxide layer 101b is an In-M-Zn oxide, the atomic ratio of the metal element of the sputtering target used for forming the In-M-Zn oxide is such that the M content is greater than or equal to In. Is preferred. As the atomic ratio of the metal elements of such a sputtering target, In: Ga: Zn = 1: 1: 1, In: Ga: Zn = 1: 3: 2, In: Ga: Zn = 1: 3: 3, In: Ga: Zn = 1: 3: 4, In: Ga: Zn = 1: 3: 5, In: Ga: Zn = 1: 3: 6, In: Ga: Zn = 1: 3: 7, In: Ga: Zn = 1: 3: 8, In: Ga: Zn = 1: 3: 9, In: Ga: Zn = 1: 3: 10, In: Ga: Zn = 1: 6: 4, In: Ga: Zn = 1: 6: 5, In: Ga: Zn = 1: 6: 6, In: Ga: Zn = 1: 6: 7, In: Ga: Zn = 1: 6: 8, In: Ga: Zn = 1: 6: 9, In: Ga: Zn = 1: 6: 10, or In: Ga: Zn = 1: 9: 4 In—Ga—Zn-based oxides with an atomic ratio and the vicinity of the composition It is preferable to use the product. Note that the atomic ratio of the metal element contained in the oxide layer 101b formed using the sputtering target varies as an error by plus or minus 20% of the atomic ratio of the metal element contained in the sputtering target. Including.

  As a method for forming the oxide layer 101b, a sputtering method, an MBE (Molecular Beam Epitaxy) method, a CVD (Chemical Vapor Deposition) method, a pulse laser deposition method, an ALD (Atomic Layer Deposition) method, or the like can be used as appropriate.

  In the case where the oxide layer 101b included in the electrode layer 101 and the oxide layer 103b included in the electrode layer 103 are formed of different materials, the electrode layer 101 and the electrode layer 103 are respectively connected to the EL layer. The injection property of electrons or holes is different.

  The oxide layer 103b different from the oxide layer 101b included in the electrode layer 103 can be formed using a conductive material that transmits light. Such a material is preferably formed using a metal, an alloy, a conductive compound, an oxide of a mixture thereof, or the like. In order that the oxide layer 103b and the conductive layer 103a do not cause electrolytic corrosion, the oxide layer 103b preferably does not contain In. As such a material, a metal oxide such as titanium oxide, tungsten oxide, or molybdenum oxide can be used.

  The transparent conductive film 101c constituting the electrode layer 101 or the transparent conductive film 103c constituting the electrode layer 103 adjusts the optical distance so that desired light from each light emitting layer can resonate and its wavelength can be increased. It can also have the function to do.

  As the transparent conductive film 101c and the transparent conductive film 103c, for example, indium tin oxide containing ITO, silicon, or silicon oxide (abbreviation: ITSO), indium zinc-oxide (Indium Zinc Oxide), tungsten oxide, and zinc oxide are included. Indium oxide or the like can be used. In particular, when the electrode layer 101 and the electrode layer 103 are used as anodes, it is preferable to use a material having a high work function (4.0 eV or more) as the transparent conductive film 101c and the transparent conductive film 103c. The transparent conductive film 101c and the transparent conductive film 103c can be formed by a sputtering method, an evaporation method, a printing method, a coating method, or the like.

  Note that in the case where a field effect transistor (FET) is formed in addition to the light-emitting element, the oxide semiconductor layer used for a channel region of the transistor and the oxide layer 101b included in the electrode layer 101 have the same element. Is preferred. That is, In and a stabilizer M (M represents Al, Si, Ti, Ga, Y, Zr, Sn, La, Ce, Nd, or Hf) in the oxide semiconductor layer used for the channel region of the transistor. It is preferable to have. The same material is particularly preferably used for the oxide semiconductor layer and the oxide layer 101b. By using a common material for the oxide semiconductor layer and the oxide layer 101b, the types of materials for forming the film are not increased, so that manufacturing costs can be reduced. In that case, the deposition process may be changed between the oxide semiconductor layer and the oxide layer 101b. That is, the pressure in the film formation chamber during film formation, the film formation gas (for example, oxygen, argon, or a mixed gas containing oxygen), film formation energy, temperature during film formation, the distance between the target and the substrate, Alternatively, the oxide semiconductor layer and the oxide layer 101b can have different properties by changing the temperature, surface treatment, and the like after film formation, whereby layers having different functions can be obtained.

  An oxide semiconductor is a semiconductor material whose resistance can be controlled by oxygen vacancies in the film and / or the concentration of impurities such as hydrogen and water in the film. Therefore, the oxide semiconductor layer and the oxide layer 101b are formed using the same material by selecting a treatment for increasing oxygen vacancies and / or impurity concentration or a treatment for reducing oxygen vacancies and / or impurity concentration. The resistivity of the oxide semiconductor layer and the oxide layer 101b can be controlled.

  Specifically, the oxide layer 101b functioning as a part of the electrode layer is subjected to plasma treatment to increase oxygen vacancies in the oxide layer 101b and / or hydrogen in the oxide layer 101b. By increasing impurities such as water, an oxide layer with high carrier density and low resistance can be obtained. Further, an oxide layer 101b is formed in contact with an insulating layer containing hydrogen, and hydrogen is diffused from the insulating layer containing hydrogen into the oxide layer 101b, whereby an oxide layer with high carrier density and low resistance is obtained. be able to.

  On the other hand, an insulating layer is preferably provided over the oxide semiconductor layer used for the channel region of the transistor so that the oxide semiconductor layer is not exposed to the plasma. Further, the insulating layer is provided so that the insulating layer containing hydrogen formed in contact with the oxide layer 101b is not in contact with. As the insulating layer provided over the oxide semiconductor layer, an insulating film capable of releasing oxygen can be used to supply oxygen to the oxide semiconductor layer. The oxide semiconductor layer to which oxygen is supplied becomes a high-resistance oxide semiconductor by filling oxygen vacancies in the film or at the interface. Note that as the insulating film from which oxygen can be released, for example, a silicon oxide film or a silicon oxynitride film can be used.

  As the plasma treatment performed on the oxide layer 101b, typically, plasma using a gas containing a kind selected from a rare gas (He, Ne, Ar, Kr, and Xe), hydrogen, and nitrogen is used. Processing. More specifically, plasma treatment in an Ar atmosphere, plasma treatment in a mixed gas atmosphere of Ar and hydrogen, plasma treatment in an ammonia atmosphere, plasma treatment in a mixed gas atmosphere of Ar and ammonia, or nitrogen For example, plasma treatment in an atmosphere.

  Through the above plasma treatment, the oxide layer 101b forms oxygen vacancies in a lattice from which oxygen is released (or a portion from which oxygen is released). The oxygen deficiency may be a factor that generates carriers. In addition, when hydrogen is supplied from the vicinity of the oxide layer 101b, more specifically, from an insulating film in contact with the lower side or the upper side of the oxide layer 101b, when the oxygen vacancies and hydrogen are combined, electrons serving as carriers May be generated. Therefore, the oxide layer 101b in which oxygen vacancies are increased by the plasma treatment is an oxide semiconductor layer having a carrier density higher than that of the oxide semiconductor layer.

Further, by using an insulating layer containing hydrogen in contact with the oxide layer 101b, in other words, a layer capable of releasing hydrogen, hydrogen can be supplied to the oxide layer 101b. The layer capable of releasing hydrogen preferably has a hydrogen concentration in the film of 1 × 10 ²² atoms / cm ³ or more. By forming such a layer in contact with the oxide layer 101b, the oxide layer 101b can contain hydrogen effectively. In this manner, the resistance of the oxide layer 101b can be arbitrarily adjusted by changing the structure of the layer in contact with the oxide layer 101b in combination with the plasma treatment described above.

On the other hand, an oxide semiconductor layer in which oxygen vacancies are filled and the hydrogen concentration is reduced can be said to be a highly purified intrinsic or substantially highly purified intrinsic oxide semiconductor layer. Here, substantially intrinsic means that the carrier density of the oxide semiconductor is less than 8 × 10 ¹¹ / cm ³ , preferably less than 1 × 10 ¹¹ / cm ³ , and more preferably 1 × 10 10. refers to is ¹⁰ / cm ³ less than 1 × ¹⁰ -9 / cm ³ or more. A highly purified intrinsic or substantially highly purified intrinsic oxide semiconductor has few carrier generation sources, and thus can have a low carrier density. In addition, a highly purified intrinsic or substantially highly purified intrinsic oxide semiconductor layer has a low defect level density; therefore, the trap level density can be reduced.

In addition, an oxide semiconductor layer that is highly purified intrinsic or substantially highly purified intrinsic has an extremely small off-state current, a source electrode even if the channel width W is 1 × 10 ⁶ μm and the channel length L is 10 μm. When the voltage between the drain electrode and the drain electrode (drain voltage) is in the range of 1V to 10V, the off-state current can be less than the measurement limit of the semiconductor parameter analyzer, that is, 1 × 10 ⁻¹³ A or less. Therefore, a transistor in which a channel region is formed in an oxide semiconductor layer has a small change in electrical characteristics and has high reliability.

  Hydrogen contained in the oxide layer 101b reacts with oxygen bonded to a metal atom to become water, and forms oxygen vacancies in a lattice from which oxygen is released (or a portion from which oxygen is released). When hydrogen enters the oxygen vacancies, electrons serving as carriers may be generated. In some cases, a part of hydrogen is bonded to oxygen bonded to a metal atom, so that an electron serving as a carrier is generated. Therefore, the oxide layer 101b containing hydrogen is an oxide semiconductor layer having a carrier density higher than that of the oxide semiconductor layer.

  In other words, the oxide layer 101b functioning as a part of the electrode layer is an oxide layer having a higher hydrogen concentration and / or oxygen deficiency than the oxide semiconductor layer included in the channel region of the transistor and having a reduced resistance.

In the oxide semiconductor layer in which the channel region of the transistor is formed, hydrogen is preferably reduced as much as possible. Specifically, in the oxide semiconductor layer, the hydrogen concentration obtained by secondary ion mass spectrometry (SIMS) is 2 × 10 ²⁰ atoms / cm ³ or less, preferably 5 × 10 ¹⁹ atoms / cm ³ or less. cm ³ or less, more preferably 1 × 10 ¹⁹ atoms / cm ³ or less, preferably less than 5 × 10 ¹⁸ atoms / cm ³ , preferably 1 × 10 ¹⁸ atoms / cm ³ or less, more preferably 5 × 10 ¹⁷ atoms / cm ³ In the following, it is more preferably 1 × 10 ¹⁶ atoms / cm ³ or less.

  In addition, heat treatment is preferably performed after an oxide semiconductor layer used for a channel region of the transistor is formed. The heat treatment is performed at a temperature of 250 ° C. or more and 650 ° C. or less, preferably 300 ° C. or more and 400 ° C. or less, more preferably 320 ° C. or more and 370 ° C. or less, in an inert gas atmosphere, an atmosphere containing an oxidizing gas of 10 ppm or more, or a reduced pressure atmosphere. Just do it. Further, the heat treatment may be performed in an atmosphere containing 10 ppm or more of an oxidizing gas in order to supplement the desorbed oxygen after the heat treatment is performed in an inert gas atmosphere. By the heat treatment here, impurities such as hydrogen and water can be removed from the oxide semiconductor layer. Note that the heat treatment may be performed before the oxide semiconductor layer is processed into an island shape.

  Note that in order to impart stable electrical characteristics to a transistor including an oxide semiconductor as a channel, it is effective to reduce the impurity concentration in the oxide semiconductor so that the oxide semiconductor is intrinsic or substantially intrinsic. .

  The thickness of the oxide semiconductor layer is 3 nm to 200 nm, preferably 3 nm to 100 nm, more preferably 3 nm to 50 nm.

  When the oxide semiconductor layer has the above-described element M in an atomic ratio greater than or equal to In, the oxide semiconductor layer may have the following effects. (1) The energy gap of the oxide semiconductor layer is increased. (2) The electron affinity of the oxide semiconductor layer is reduced. (3) Shield impurities from the outside. (4) The insulation is increased. In addition, since the element M is a metal element having a strong binding force with oxygen, oxygen vacancies are less likely to occur by having M in an atomic ratio greater than or equal to In.

  Note that the oxide semiconductor layer is not limited to those described above, and an oxide semiconductor layer that has an appropriate composition may be used depending on required semiconductor characteristics and electrical characteristics (such as field-effect mobility and threshold voltage) of a transistor. In addition, in order to obtain the required semiconductor characteristics of the transistor, the carrier density, impurity concentration, defect density, atomic ratio of metal element to oxygen, interatomic distance, density, etc. of the oxide semiconductor layer should be appropriate. Is preferred.

The electrode layer 102 functions as an anode or a cathode of each light emitting element. Note that in the case where the electrode layer 101 has a function of reflecting light, the electrode layer 102 is preferably formed using a conductive material having a function of transmitting light. The conductive material is a conductive material having a visible light transmittance of 40% to 100%, preferably 60% to 100%, and a resistivity of 1 × 10 ⁻² Ω · cm or less. Can be mentioned. The electrode layer 102 may be formed using a conductive material having a function of transmitting light and a function of reflecting light. Examples of the conductive material include a conductive material having a visible light reflectance of 20% to 80%, preferably 40% to 70%, and a resistivity of 1 × 10 ⁻² Ω · cm or less. Can be mentioned. In the case where the electrode layer 101 has a function of transmitting light, the electrode layer 102 is preferably formed using a conductive material having a function of reflecting light.

  The electrode layer 102 can be formed using one or more kinds of conductive metals, alloys, conductive compounds, and the like. For example, ITO, ITSO, indium zinc-oxide (indium zinc oxide), indium oxide-tin oxide containing titanium, indium-titanium oxide, indium oxide containing tungsten oxide, and zinc oxide can be used. . In addition, a metal thin film having a thickness that transmits light (preferably, approximately 5 nm to 30 nm) can be used. As the metal, for example, Ag or an alloy such as Ag and Al, Ag and Mg, Ag and Au, Ag and Yb, or the like can be used. In particular, when the electrode layer 102 has a function as a cathode, a material having at least one selected from In, Ag, and Mg is preferable. In addition, it is preferable to use a material having a low work function (3.8 eV or less). For example, elements belonging to Group 1 or Group 2 of the periodic table (alkali metals such as lithium and cesium, alkaline earth metals such as calcium and strontium, magnesium, etc.), and alloys containing these elements (eg, Ag-Mg) Al-Li), rare earth metals such as europium and ytterbium, alloys containing these rare earth metals, alloys containing aluminum and silver, and the like can be used. The electrode layer 102 can be formed by a sputtering method, an evaporation method, a printing method, a coating method, or the like.

  The material exemplified for the electrode layer 101 or the electrode layer 103 can be used for the electrode layer 104.

≪Luminescent layer≫
The light-emitting layer 120, the light-emitting layer 121, or the light-emitting layer 122 preferably includes a first compound that emits at least one selected from purple, blue, and blue-green. Or it is preferable to have the 2nd compound which exhibits at least any one light emission chosen from green, yellowish green, yellow, orange, or red. Each light emitting layer includes one or both of an electron transporting material and a hole transporting material in addition to the first compound. Each light-emitting layer preferably includes one or both of an electron transporting material and a hole transporting material in addition to the second compound.

  In addition, as the first compound and the second compound, a luminescent substance that changes singlet excitation energy into light emission or a luminescent substance that changes triplet excitation energy into light emission can be used. Examples of the luminescent substance include the following.

  Examples of the light-emitting substance that changes singlet excitation energy into light emission include substances that emit fluorescence, such as 5,6-bis [4- (10-phenyl-9-anthryl) phenyl] -2,2′-bipyridine. (Abbreviation: PAP2BPy), 5,6-bis [4 ′-(10-phenyl-9-anthryl) biphenyl-4-yl] -2,2′-bipyridine (abbreviation: PAPP2BPy), N, N′-bis [ 4- (9H-carbazol-9-yl) phenyl] -N, N′-diphenylstilbene-4,4′-diamine (abbreviation: YGA2S), 4- (9H-carbazol-9-yl) -4 ′-( 10-phenyl-9-anthryl) triphenylamine (abbreviation: YGAPA), 4- (9H-carbazol-9-yl) -4 ′-(9,10-diphenyl-2-anthryl) to Phenylamine (abbreviation: 2YGAPPA), N, 9-diphenyl-N- [4- (10-phenyl-9-anthryl) phenyl] -9H-carbazol-3-amine (abbreviation: PCAPA), 4- (10-phenyl) -9-anthryl) -4 '-(9-phenyl-9H-carbazol-3-yl) triphenylamine (abbreviation: PCBAPA), 4- [4- (10-phenyl-9-anthryl) phenyl] -4' -(9-phenyl-9H-carbazol-3-yl) triphenylamine (abbreviation: PCBAPBA), perylene, 2,5,8,11-tetra (tert-butyl) perylene (abbreviation: TBP), N, N ' -Bis [4- (9-phenyl-9H-fluoren-9-yl) phenyl] -N, N'-diphenylpyrene-1,6-diamine (abbreviation: 1 6FLPAPrn), N, N′-bis (3-methylphenyl) -N, N′-bis [3- (9-phenyl-9H-fluoren-9-yl) phenyl] -pyrene-1,6-diamine (abbreviation) : 1,6 mMemFLPAPrn), N, N ″-(2-tert-butylanthracene-9,10-diyldi-4,1-phenylene) bis [N, N ′, N′-triphenyl-1,4-phenylene Diamine] (abbreviation: DPABPA), N, 9-diphenyl-N- [4- (9,10-diphenyl-2-anthryl) phenyl] -9H-carbazol-3-amine (abbreviation: 2PCAPPA), N- [4 -(9,10-diphenyl-2-anthryl) phenyl] -N, N ′, N′-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPPA), N, N, N ', N', N ″, N ″, N ′ ″, N ′ ″-octaphenyldibenzo [g, p] chrysene-2,7,10,15-tetraamine (abbreviation: DBC1), Coumarin 30 N- (9,10-diphenyl-2-anthryl) -N, 9-diphenyl-9H-carbazol-3-amine (abbreviation: 2PCAPA), N- (9,10-diphenyl-2-anthryl) -N, N ′, N′-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPA), N, N, 9-triphenylanthracen-9-amine (abbreviation: DPhAPhA), coumarin 6, coumarin 545T, N, N ′ -Diphenylquinacridone (abbreviation: DPQd), rubrene, 5,12-bis (1,1'-biphenyl-4-yl) -6,11-diphenyltetracene (abbreviation: BPT), 2 (2- {2- [4- (dimethylamino) phenyl] ethenyl} -6-methyl-4H-pyran-4-ylidene) propanedinitrile (abbreviation: DCM1), 2- {2-methyl-6- [2 -(2,3,6,7-tetrahydro-1H, 5H-benzo [ij] quinolizin-9-yl) ethenyl] -4H-pyran-4-ylidene} propanedinitrile (abbreviation: DCM2), N, N, N ′, N′-tetrakis (4-methylphenyl) tetracene-5,11-diamine (abbreviation: p-mPhTD), 7,14-diphenyl-N, N, N ′, N′-tetrakis (4-methylphenyl) Acenaphtho [1,2-a] fluoranthene-3,10-diamine (abbreviation: p-mPhAFD), 2- {2-isopropyl-6- [2- (1,1,7,7-tetramethyl-2, 3, , 7-tetrahydro-1H, 5H-benzo [ij] quinolidin-9-yl) ethenyl] -4H-pyran-4-ylidene} propanedinitrile (abbreviation: DCJTI), 2- {2-tert-butyl-6 [2- (1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H, 5H-benzo [ij] quinolizin-9-yl) ethenyl] -4H-pyran-4-ylidene} Propanedinitrile (abbreviation: DCJTB), 2- (2,6-bis {2- [4- (dimethylamino) phenyl] ethenyl} -4H-pyran-4-ylidene) propanedinitrile (abbreviation: BisDCM), 2 -{2,6-bis [2- (8-methoxy-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H, 5H-benzo [ij] quinolidin-9-yl) D Tenenyl] -4H-pyran-4-ylidene} propanedinitrile (abbreviation: BisDCJTM), 5,10,15,20-tetraphenylbisbenzo [5,6] indeno [1,2,3-cd: 1 ′, 2 ′, 3′-lm] perylene, etc., a substance having an anthracene skeleton, tetracene skeleton, chrysene skeleton, phenanthrene skeleton, pyrene skeleton, perylene skeleton, stilbene skeleton, acridone skeleton, coumarin skeleton, phenoxazine skeleton, phenothiazine skeleton, etc. Can be used.

  Examples of the light-emitting substance that changes triplet excitation energy into light emission include a substance that emits phosphorescence.

As a substance having an emission peak in blue or green, for example, tris {2- [5- (2-methylphenyl) -4- (2,6-dimethylphenyl) -4H-1,2,4-triazole-3 -Yl- [kappa] N2] phenyl- [kappa] C} iridium (III) (abbreviation: Ir (mppptz-dmp) ₃ ), tris (5-methyl-3,4-diphenyl-4H-1,2,4-triazolate) iridium (III ) (Abbreviation: Ir (Mptz) ₃ ), tris [4- (3-biphenyl) -5-isopropyl-3-phenyl-4H-1,2,4-triazolato] iridium (III) (abbreviation: Ir (iPrptz- 3b) ₃ ), tris [3- (5-biphenyl) -5-isopropyl-4-phenyl-4H-1,2,4-triazolato] iridium (III) (abbreviation: Ir (IPr5btz) ₃ ), an organometallic iridium complex having a 4H-triazole skeleton, or tris [3-methyl-1- (2-methylphenyl) -5-phenyl-1H-1,2,4-triazolate] Iridium (III) (abbreviation: Ir (Mptz1-mp) ₃ ), tris (1-methyl-5-phenyl-3-propyl-1H-1,2,4-triazolato) iridium (III) (abbreviation: Ir (Prptz1) -Me) ₃ ) an organometallic iridium complex having a 1H-triazole skeleton, fac-tris [1- (2,6-diisopropylphenyl) -2-phenyl-1H-imidazole] iridium (III) (abbreviation: Ir _{(iPrpmi) 3),} tris [3- (2,6-dimethylphenyl) -7-methylimidazo [1, 2-f] Enantorijinato] iridium (III) _{(abbreviation: Ir (dmpimpt-Me) 3} ) or an organic iridium complex having an imidazole skeleton, such as bis [2- (4 ', 6'-difluorophenyl) pyridinato -N, ^{C 2 '} ] Iridium (III) tetrakis (1-pyrazolyl) borate (abbreviation: FIr6), bis [2- (4 ′, 6′-difluorophenyl) pyridinato-N, C ^{2 ′} ] iridium (III) picolinate (abbreviation: FIrpic) ), Bis {2- [3 ′, 5′-bis (trifluoromethyl) phenyl] pyridinato-N, C ^{2 ′} } iridium (III) picolinate (abbreviation: Ir (CF ₃ ppy) ₂ (pic)), bis [2- (4 ', 6'-difluorophenyl) pyridinato -N, C ^2'] iridium (III) acetylacetonate Abbreviation: FIr (acac)) organometallic iridium complex having a ligand of phenylpyridine derivative having an electron-withdrawing group such as and the like. Among the above, an organometallic iridium complex having a 4H-triazole skeleton is particularly preferable because it is excellent in reliability and luminous efficiency.

Examples of a substance having an emission peak in green or yellow include tris (4-methyl-6-phenylpyrimidinato) iridium (III) (abbreviation: Ir (mppm) ₃ ), tris (4-t-butyl). -6-phenylpyrimidinato) iridium (III) (abbreviation: Ir (tBupppm) ₃ ), (acetylacetonato) bis (6-methyl-4-phenylpyrimidinato) iridium (III) (abbreviation: Ir (mppm) ) ₂ (acac)), (acetylacetonato) bis (6-tert-butyl-4-phenylpyrimidinato) iridium (III) (abbreviation: Ir (tBupppm) ₂ (acac)), (acetylacetonato) bis [4- (2-norbornyl) -6-phenylpyrimidinato] iridium (III) (abbreviation: Ir (nbppm) ₂ (Acac)), (acetylacetonato) bis [5-methyl-6- (2-methylphenyl) -4-phenylpyrimidinato] iridium (III) (abbreviation: Ir (mpmppm) ₂ (acac)), ( Acetylacetonato) bis {4,6-dimethyl-2- [6- (2,6-dimethylphenyl) -4-pyrimidinyl-κN3] phenyl-κC} iridium (III) (abbreviation: Ir (dmppm-dmp) ₂ (Acac)), (acetylacetonato) bis (4,6-diphenylpyrimidinato) iridium (III) (abbreviation: Ir (dppm) ₂ (acac)), an organometallic iridium complex having a pyrimidine skeleton, (Acetylacetonato) bis (3,5-dimethyl-2-phenylpyrazinato) iridium (III) (abbreviation: Ir (mppr -Me) ₂ (acac)), (acetylacetonato) bis (5-isopropyl-3-methyl-2-phenylpyrazinato) iridium (III) (abbreviation: Ir (mppr-iPr) ₂ (acac)) Organometallic iridium complexes having such a pyrazine skeleton, tris (2-phenylpyridinato-N, C ^{2 ′} ) iridium (III) (abbreviation: Ir (ppy) ₃ ), bis (2-phenylpyridinato- N, C ^{2 ′} ) iridium (III) acetylacetonate (abbreviation: Ir (ppy) ₂ (acac)), bis (benzo [h] quinolinato) iridium (III) acetylacetonate (abbreviation: Ir (bzq) ₂ ( acac)), tris (benzo [h] quinolinato) iridium (III) (abbreviation: Ir _(bzq) 3), tris (2-Fenirukino Isocyanato -N, C ^{2 ')} iridium (III) (abbreviation: Ir _(pq) 3), bis (2-phenylquinolinato--N, C ^2') iridium (III) acetylacetonate (abbreviation: Ir (pq) ₂ (acac)), an organometallic iridium complex having a pyridine skeleton, or bis (2,4-diphenyl-1,3-oxazolate-N, C ^{2 ′} ) iridium (III) acetylacetonate (abbreviation: Ir ( dpo) ₂ (acac)), bis {2- [4 ′-(perfluorophenyl) phenyl] pyridinato-N, C ^{2 ′} } iridium (III) acetylacetonate (abbreviation: Ir (p-PF-ph) ₂ (Acac)), bis (2-phenylbenzothiazolate-N, C ^{2 ′} ) iridium (III) acetylacetonate (abbreviation: Ir (bt) ₂ (acac )) And other rare earth metal complexes such as tris (acetylacetonato) (monophenanthroline) terbium (III) (abbreviation: Tb (acac) ₃ (Phen)). Among the above-described compounds, organometallic iridium complexes having a pyrimidine skeleton are particularly preferable because they are remarkably excellent in reliability and luminous efficiency.

As a substance having an emission peak in yellow or red, for example, (diisobutyrylmethanato) bis [4,6-bis (3-methylphenyl) pyrimidinato] iridium (III) (abbreviation: Ir (5 mdppm) ₂ ( dibm)), bis [4,6-bis (3-methylphenyl) pyrimidinato] (dipivaloylmethanato) iridium (III) (abbreviation: Ir (5 mdppm) ₂ (dpm)), bis [4,6-di (Naphthalen-1-yl) pyrimidinato] (dipivaloylmethanato) iridium (III) (abbreviation: Ir (d1npm) ₂ (dpm)), an organometallic iridium complex having a pyrimidine skeleton, and (acetylacetonato) bis (2,3,5-triphenylpyrazinato) iridium (III) (abbreviation: Ir _(tppr) 2 (ac c)), bis (2,3,5-triphenylpyrazinato) (dipivaloylmethanato) iridium (III) (abbreviation: Ir _(tppr) 2 (dpm)), (acetylacetonato) bis [2 , 3-bis (4-fluorophenyl) quinoxalinato] iridium (III) (abbreviation: [Ir (Fdpq) ₂ (acac)]), organometallic iridium complexes having a pyrazine skeleton, tris (1-phenylisoquino Linato-N, C ^{2 ′} ) iridium (III) (abbreviation: Ir (piq) ₃ ), bis (1-phenylisoquinolinato-N, C ^{2 ′} ) iridium (III) acetylacetonate (abbreviation: Ir (piq) ) other organometallic iridium complex having a pyridine skeleton, such as ₂ (acac)), 2,3,7,8,12,13,17,18-octaethyl Platinum complexes such as 21H, 23H-porphyrin platinum (II) (abbreviation: PtOEP), tris (1,3-diphenyl-1,3-propanedionate) (monophenanthroline) europium (III) (abbreviation: Eu ( DBM) ₃ (Phen)), tris [1- (2-thenoyl) -3,3,3-trifluoroacetonato] (monophenanthroline) europium (III) (abbreviation: Eu (TTA) ₃ (Phen)) Such rare earth metal complexes are mentioned. Among the above-described compounds, organometallic iridium complexes having a pyrimidine skeleton are particularly preferable because they are remarkably excellent in reliability and luminous efficiency. An organometallic iridium complex having a pyrazine skeleton can emit red light with good chromaticity.

A material that can be used as a host material of the light-emitting layer is not particularly limited. For example, tris (8-quinolinolato) aluminum (III) (abbreviation: Alq), tris (4-methyl-8-quinolinolato) aluminum (III) (abbreviation: Almq ₃ ), bis (10-hydroxybenzo [h] quinolinato) beryllium (II) (abbreviation: BeBq ₂ ), bis (2-methyl-8-quinolinolato) (4-phenylphenolato) aluminum (III) (abbreviation: BAlq), bis (8-quinolinolato) zinc (II) (abbreviation: Znq), bis [2- (2-benzoxazolyl) phenolato] zinc (II) (abbreviation: ZnPBO), bis Metal complexes such as [2- (2-benzothiazolyl) phenolato] zinc (II) (abbreviation: ZnBTZ), 2- (4-bifu Enilyl) -5- (4-tert-butylphenyl) -1,3,4-oxadiazole (abbreviation: PBD), 1,3-bis [5- (p-tert-butylphenyl) -1,3, 4-oxadiazol-2-yl] benzene (abbreviation: OXD-7), 3- (4-biphenylyl) -4-phenyl-5- (4-tert-butylphenyl) -1,2,4-triazole ( Abbreviation: TAZ), 2,2 ′, 2 ″-(1,3,5-benzenetriyl) tris (1-phenyl-1H-benzimidazole) (abbreviation: TPBI), bathophenanthroline (abbreviation: Bphen), Heterocyclic compounds such as bathocuproin (abbreviation: BCP), 9- [4- (5-phenyl-1,3,4-oxadiazol-2-yl) phenyl] -9H-carbazole (abbreviation: CO11), 4, '-Bis [N- (1-naphthyl) -N-phenylamino] biphenyl (abbreviation: NPB), N, N'-bis (3-methylphenyl) -N, N'-diphenyl- [1,1'- Biphenyl] -4,4′-diamine (abbreviation: TPD), 4,4′-bis [N- (spiro-9,9′-bifluoren-2-yl) -N-phenylamino] biphenyl (abbreviation: BSPB) And aromatic amine compounds such as In addition, condensed polycyclic aromatic compounds such as anthracene derivatives, phenanthrene derivatives, pyrene derivatives, chrysene derivatives, and dibenzo [g, p] chrysene derivatives can be given. Specifically, 9,10-diphenylanthracene (abbreviation: DPAnth) N, N-diphenyl-9- [4- (10-phenyl-9-anthryl) phenyl] -9H-carbazol-3-amine (abbreviation: CzA1PA), 4- (10-phenyl-9-anthryl) triphenyl Amine (abbreviation: DPhPA), YGAPA, PCAPA, N, 9-diphenyl-N- {4- [4- (10-phenyl-9-anthryl) phenyl] phenyl} -9H-carbazol-3-amine (abbreviation: PCAPBA) ) 2PCAPA, 6,12-dimethoxy-5,11-diphenylchrysene, DBC1, -[4- (10-phenyl-9-anthracenyl) phenyl] -9H-carbazole (abbreviation: CzPA), 3,6-diphenyl-9- [4- (10-phenyl-9-anthryl) phenyl] -9H- Carbazole (abbreviation: DPCzPA), 9,10-bis (3,5-diphenylphenyl) anthracene (abbreviation: DPPA), 9,10-di (2-naphthyl) anthracene (abbreviation: DNA), 2-tert-butyl- 9,10-di (2-naphthyl) anthracene (abbreviation: t-BuDNA), 9,9′-bianthryl (abbreviation: BANT), 9,9 ′-(stilbene-3,3′-diyl) diphenanthrene (abbreviation) : DPNS), 9,9 ′-(stilbene-4,4′-diyl) diphenanthrene (abbreviation: DPNS2), 1,3,5-tri (1-pyrenyl) ben Zen (abbreviation: TPB3) can be given. From these and various substances, one or a plurality of substances having an energy gap larger than that of the light emitting material may be selected and used. When the light-emitting substance is a substance that emits phosphorescence, a host material that has a triplet excitation energy higher than the triplet excitation energy (the energy difference between the ground state and the triplet excited state) of the light-emitting substance is selected. It ’s fine.

  Further, when a plurality of materials are used as the host material of the light emitting layer, it is preferable to use a combination of two types of compounds that form an exciplex. In this case, various carrier transport materials can be used as appropriate. However, in order to efficiently form an exciplex, a compound that easily receives electrons (a material having an electron transport property) and a compound that easily receives holes (holes) It is particularly preferred to combine with a material having transportability.

  This is because when a material having an electron transporting property and a material having a hole transporting property are combined to form a host material that forms an exciplex, the mixing ratio of the material having the electron transporting property and the material having the hole transporting property is By adjusting, it becomes easy to optimize the carrier balance of holes and electrons in the light emitting layer. By optimizing the carrier balance between holes and electrons in the light emitting layer, it is possible to suppress the bias of the region where recombination of electrons and holes occurs in the light emitting layer. By suppressing the bias of the region where recombination occurs, the reliability of the light-emitting element can be improved.

  As a compound that easily receives electrons (a material having an electron transporting property), a π-electron deficient heteroaromatic such as a nitrogen-containing heteroaromatic compound, a metal complex, or the like can be used. Specifically, bis (10-hydroxybenzo [h] quinolinato) beryllium (II) (abbreviation: BeBq2), bis (2-methyl-8-quinolinolato) (4-phenylphenolato) aluminum (III) (abbreviation: BAlq), bis (8-quinolinolato) zinc (II) (abbreviation: Znq), bis [2- (2-benzoxazolyl) phenolato] zinc (II) (abbreviation: ZnPBO), bis [2- (2- Benzothiazolyl) phenolato] zinc (II) (abbreviation: ZnBTZ) or a metal complex such as 2- (4-biphenylyl) -5- (4-tert-butylphenyl) -1,3,4-oxadiazole (abbreviation: PBD), 3- (4-biphenylyl) -4-phenyl-5- (4-tert-butylphenyl) -1,2,4-triazole (abbreviation: TAZ), 1 3-bis [5- (p-tert-butylphenyl) -1,3,4-oxadiazol-2-yl] benzene (abbreviation: OXD-7), 9- [4- (5-phenyl-1, 3,4-oxadiazol-2-yl) phenyl] -9H-carbazole (abbreviation: CO11), 2,2 ′, 2 ″-(1,3,5-benzenetriyl) tris (1-phenyl- 1H-benzimidazole) (abbreviation: TPBI), 2- [3- (dibenzothiophen-4-yl) phenyl] -1-phenyl-1H-benzimidazole (abbreviation: mDBTBIm-II) and other heterocyclic rings having an azole skeleton Compounds, 2- [3- (dibenzothiophen-4-yl) phenyl] dibenzo [f, h] quinoxaline (abbreviation: 2mDBTPDBq-II), 2- [3 ′-(dibenzothiophene) -4-yl) biphenyl-3-yl] dibenzo [f, h] quinoxaline (abbreviation: 2mDBTBPDBq-II), 2- [3 ′-(9H-carbazol-9-yl) biphenyl-3-yl] dibenzo [f H] quinoxaline (abbreviation: 2mCzBPDBq), 2- [4- (3,6-diphenyl-9H-carbazol-9-yl) phenyl] dibenzo [f, h] quinoxaline (abbreviation: 2CzPDBq-III), 7- [ 3- (dibenzothiophen-4-yl) phenyl] dibenzo [f, h] quinoxaline (abbreviation: 7mDBTPDBq-II) and 6- [3- (dibenzothiophen-4-yl) phenyl] dibenzo [f, h] Quinoxaline (abbreviation: 6mDBTPDBq-II), 4,6-bis [3- (phenanthren-9-yl) phenyl] pyri Midine (abbreviation: 4,6mPnP2Pm), 4,6-bis [3- (4-dibenzothienyl) phenyl] pyrimidine (abbreviation: 4,6mDBTP2Pm-II), 4,6-bis [3- (9H-carbazole-9 A heterocyclic compound having a diazine skeleton such as -yl) phenyl] pyrimidine (abbreviation: 4,6mCzP2Pm), and 2- {4- [3- (N-phenyl-9H-carbazol-3-yl) -9H-carbazole- 9-yl] phenyl} -4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn) and other heterocyclic compounds having a triazine skeleton, and 3,5-bis [3- (9H-carbazole-9 -Yl) phenyl] pyridine (abbreviation: 35DCzPPy), 1,3,5-tri [3- (3-pyridyl) phenyl] benzene (abbreviation: TmP) Heterocyclic compounds having a pyridine skeleton such PB) and the like. Among the compounds described above, a heterocyclic compound having a diazine skeleton and a triazine skeleton and a heterocyclic compound having a pyridine skeleton are preferable because they have good reliability. In particular, a heterocyclic compound having a diazine (pyrimidine or pyrazine) skeleton and a triazine skeleton has a high electron transport property and contributes to a reduction in driving voltage.

  As a compound that easily accepts holes (a material having a hole transporting property), a π-electron rich heteroaromatic (for example, a carbazole derivative or an indole derivative) or an aromatic amine can be preferably used. Specifically, 2- [N- (9-phenylcarbazol-3-yl) -N-phenylamino] spiro-9,9′-bifluorene (abbreviation: PCASF), 4,4 ′, 4 ″ -Tris [N- (1-naphthyl) -N-phenylamino] triphenylamine (abbreviation: 1′-TNATA), 2,7-bis [N- (4-diphenylaminophenyl) -N-phenylamino] -spiro- 9,9′-bifluorene (abbreviation: DPA2SF), N, N′-bis (9-phenylcarbazol-3-yl) -N, N′-diphenylbenzene-1,3-diamine (abbreviation: PCA2B), N— (9,9-dimethyl-2-diphenylamino-9H-fluoren-7-yl) diphenylamine (abbreviation: DPNF), N, N ′, N ″ -triphenyl-N, N ′, N ″ -tris ( -Phenylcarbazol-3-yl) benzene-1,3,5-triamine (abbreviation: PCA3B), 2- [N- (9-phenylcarbazol-3-yl) -N-phenylamino] spiro-9,9 ' -Bifluorene (abbreviation: PCASF), 2- [N- (4-diphenylaminophenyl) -N-phenylamino] spiro-9,9'-bifluorene (abbreviation: DPASF), N, N'-bis [4- ( Carbazol-9-yl) phenyl] -N, N′-diphenyl-9,9-dimethylfluorene-2,7-diamine (abbreviation: YGA2F), 4,4′-bis [N- (1-naphthyl) -N -Phenylamino] biphenyl (abbreviation: NPB), N, N′-bis (3-methylphenyl) -N, N′-diphenyl- [1,1′-biphenyl] -4,4′-diamine ( Name: TPD), 4,4′-bis [N- (4-diphenylaminophenyl) -N-phenylamino] biphenyl (abbreviation: DPAB), 4,4′-bis [N- (spiro-9,9 ′) -Bifluoren-2-yl) -N-phenylamino] biphenyl (abbreviation: BSPB), 4-phenyl-4 '-(9-phenylfluoren-9-yl) triphenylamine (abbreviation: BPAFLP), 4-phenyl- 3 ′-(9-phenylfluoren-9-yl) triphenylamine (abbreviation: mBPAFLP), N- (9,9-dimethyl-9H-fluoren-2-yl) -N- {9,9-dimethyl-2 -[N'-phenyl-N '-(9,9-dimethyl-9H-fluoren-2-yl) amino] -9H-fluoren-7-yl} phenylamine (abbreviation: DFLADFL), 3 -[N- (9-phenylcarbazol-3-yl) -N-phenylamino] -9-phenylcarbazole (abbreviation: PCzPCA1), 3- [N- (4-diphenylaminophenyl) -N-phenylamino]- 9-phenylcarbazole (abbreviation: PCzDPA1), 3,6-bis [N- (4-diphenylaminophenyl) -N-phenylamino] -9-phenylcarbazole (abbreviation: PCzDPA2), 4,4′-bis (N -{4- [N '-(3-methylphenyl) -N'-phenylamino] phenyl} -N-phenylamino) biphenyl (abbreviation: DNTPD), 3,6-bis [N- (4-diphenylaminophenyl) ) -N- (1-naphthyl) amino] -9-phenylcarbazole (abbreviation: PCzTPN2), 3,6-bis [N- (9-pheny Carbazol-3-yl) -N-phenylamino] -9-phenylcarbazole (abbreviation: PCzPCA2), 4-phenyl-4 ′-(9-phenyl-9H-carbazol-3-yl) triphenylamine (abbreviation: PCBA1BP) ), 4,4′-diphenyl-4 ″-(9-phenyl-9H-carbazol-3-yl) triphenylamine (abbreviation: PCBBi1BP), 4- (1-naphthyl) -4 ′-(9-phenyl) -9H-carbazol-3-yl) triphenylamine (abbreviation: PCBANB), 4,4'-di (1-naphthyl) -4 "-(9-phenyl-9H-carbazol-3-yl) triphenylamine (Abbreviation: PCBNBB), 3- [N- (1-naphthyl) -N- (9-phenylcarbazol-3-yl) amino] -9-phenyl Ruvazole (abbreviation: PCzPCN1), 9,9-dimethyl-N-phenyl-N- [4- (9-phenyl-9H-carbazol-3-yl) phenyl] fluoren-2-amine (abbreviation: PCBAF), N- Phenyl-N- [4- (9-phenyl-9H-carbazol-3-yl) phenyl] -spiro-9,9′-bifluoren-2-amine (abbreviation: PCBASF), N- (4-biphenyl) -N -(9,9-dimethyl-9H-fluoren-2-yl) -9-phenyl-9H-carbazol-3-amine (abbreviation: PCBiF), N- (1,1'-biphenyl-4-yl) -N -Aromatic amine bones such as [4- (9-phenyl-9H-carbazol-3-yl) phenyl] -9,9-dimethyl-9H-fluoren-2-amine (abbreviation: PCBBiF) Compounds having a rating, 1,3-bis (N-carbazolyl) benzene (abbreviation: mCP), 4,4′-di (N-carbazolyl) biphenyl (abbreviation: CBP), 3,6-bis (3,5 -Diphenylphenyl) -9-phenylcarbazole (abbreviation: CzTP), 9-phenyl-9H-3- (9-phenyl-9H-carbazol-3-yl) carbazole (abbreviation: PCCP) and other compounds having a carbazole skeleton, 4,4 ′, 4 ″-(benzene-1,3,5-triyl) tri (dibenzothiophene) (abbreviation: DBT3P-II), 2,8-diphenyl-4- [4- (9-phenyl-) 9H-Fluoren-9-yl) phenyl] dibenzothiophene (abbreviation: DBTFLP-III), 4- [4- (9-phenyl-9H-fluoren-9-yl) pheny ] -6-phenyldibenzothiophene (abbreviation: DBTFLP-IV) and other compounds having a thiophene skeleton, and 4,4 ′, 4 ″-(benzene-1,3,5-triyl) tri (dibenzofuran) (abbreviation: DBF3P-II), 4- {3- [3- (9-phenyl-9H-fluoren-9-yl) phenyl] phenyl} dibenzofuran (abbreviation: mmDBFFLBi-II) and the like are included. Among the compounds described above, a compound having an aromatic amine skeleton and a compound having a carbazole skeleton are preferable because they have good reliability, high hole transportability, and contribute to reduction in driving voltage.

  Note that the host material combination for forming the exciplex is not limited to the above-described compounds, and is a combination capable of transporting carriers and forming an exciplex. The emission of the exciplex is absorbed by the luminescent substance. As long as it overlaps with the absorption band on the longest wavelength side in the spectrum (absorption corresponding to the transition from the singlet ground state to the singlet excited state of the light-emitting substance), other materials may be used.

  Further, a thermally activated delayed fluorescence (TADF) body may be used as a light emitting material or a host material of the light emitting layer. Thermally activated delayed phosphor is a material that has a small difference between triplet excitation energy level and singlet excitation energy level, and has a function of converting energy from a triplet excited state to a singlet excited state by reverse intersystem crossing. It is.

  The thermally activated delayed phosphor may be composed of one type of material or a plurality of materials. For example, when the thermally activated delayed phosphor is composed of one type of material, the following materials can be used.

First, fullerenes and derivatives thereof, acridine derivatives such as proflavine, eosin and the like can be mentioned. In addition, metal-containing porphyrins including magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In), palladium (Pd), and the like can be given. Examples of the metal-containing porphyrin include a protoporphyrin-tin fluoride complex (SnF ₂ (Proto IX)), a mesoporphyrin-tin fluoride complex (SnF ₂ (Meso IX)) represented by the following structural formula, and hematoporphyrin. - tin fluoride complex _{(SnF 2 (Hemato IX))} , coproporphyrin tetramethyl ester - tin fluoride complex _{(SnF 2 (Copro III-4Me} )), octaethylporphyrin - tin fluoride complex _(SnF 2 _(OEP)) , Etioporphyrin-tin fluoride complex (SnF ₂ (Etio I)), octaethylporphyrin-platinum chloride complex (PtCl ₂ OEP), and the like.

  In addition, as a thermally activated delayed phosphor composed of a kind of material, 2- (biphenyl-4-yl) -4,6-bis (12-phenylindolo [2,3] represented by the following structural formula -A] carbazol-11-yl) -1,3,5-triazine (abbreviation: PIC-TRZ), 2- {4- [3- (N-phenyl-9H-carbazol-3-yl) -9H-carbazole -9-yl] phenyl} -4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn), 2- [4- (10H-phenoxazin-10-yl) phenyl] -4,6-diphenyl -1,3,5-triazine (abbreviation: PXZ-TRZ), 3- [4- (5-phenyl-5,10-dihydrophenazin-10-yl) phenyl] -4,5-diphenyl-1,2, 4-triazole ( Name: PPZ-3TPT), 3- (9,9-dimethyl-9H-acridin-10-yl) -9H-xanthen-9-one (abbreviation: ACRXTN), bis [4- (9,9-dimethyl-9) , 10-dihydroacridine) phenyl] sulfone (abbreviation: DMAC-DPS), 10-phenyl-10H, 10′H-spiro [acridine-9,9′-anthracene] -10′-one (abbreviation: ACRSA), etc. A heterocyclic compound having a π-electron rich heteroaromatic ring and a π-electron deficient heteroaromatic ring can also be used. Since the heterocyclic compound has a π-electron rich heteroaromatic ring and a π-electron deficient heteroaromatic ring, it is preferable because of its high electron transporting property and hole transporting property. A substance in which a π-electron rich heteroaromatic ring and a π-electron deficient heteroaromatic ring are directly bonded has both a donor property of a π-electron rich heteroaromatic ring and an acceptor property of a π-electron deficient heteroaromatic ring, This is particularly preferable because the difference between the singlet excitation energy level and the triplet excitation energy level is small.

  Moreover, when using a thermally activated delayed fluorescent substance as a host material, it is preferable to use combining two types of compounds which form an exciplex. In this case, it is particularly preferable to use a compound that easily receives electrons, which is a combination that forms the exciplex shown above, and a compound that easily receives holes.

≪Hole injection layer≫
The hole injection layer 111 and the hole injection layer 116 are layers that inject holes from the anode into the EL layer, and are layers that contain a substance with a high hole injection property. For example, transition metal oxides such as molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, and manganese oxide can be used. In addition, phthalocyanine compounds such as phthalocyanine (abbreviation: H ₂ Pc) and copper phthalocyanine (abbreviation: CuPc), 4,4′-bis [N- (4-diphenylaminophenyl) -N-phenylamino] biphenyl ( Abbreviation: DPAB), N, N′-bis {4- [bis (3-methylphenyl) amino] phenyl} -N, N′-diphenyl- (1,1′-biphenyl) -4,4′-diamine ( The hole injection layer is also formed by an aromatic amine compound such as abbreviation: DNTPD, or a polymer such as poly (3,4-ethylenedioxythiophene) / poly (styrenesulfonic acid) (abbreviation: PEDOT / PSS). can do.

  For the hole injection layer, a composite material including a hole transporting material and an acceptor substance can be used. By including a hole transporting material and an acceptor substance, electrons are extracted from the hole transporting material by the acceptor substance to generate holes, and holes are formed in the light emitting layer through the hole transport layer. Is injected.

As a hole-transporting material used for the hole-injecting layer 111 and the hole-injecting layer 116, for example, 4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (abbreviation: NPB or α) -NPD), N, N′-bis (3-methylphenyl) -N, N′-diphenyl- [1,1′-biphenyl] -4,4′-diamine (abbreviation: TPD), 4,4 ′, 4 ″ -tris (carbazol-9-yl) triphenylamine (abbreviation: TCTA), 4,4 ′, 4 ″ -tris (N, N-diphenylamino) triphenylamine (abbreviation: TDATA), 4, 4 ′, 4 ″ -tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine (abbreviation: MTDATA), 4,4′-bis [N- (spiro-9,9′-bifluorene) -2-yl) -N-phenylamino] biphenyl Aromatic amine compounds such as (abbreviation: BSPB), 3- [N- (9-phenylcarbazol-3-yl) -N-phenylamino] -9-phenylcarbazole (abbreviation: PCzPCA1), 3,6-bis [ N- (9-phenylcarbazol-3-yl) -N-phenylamino] -9-phenylcarbazole (abbreviation: PCzPCA2), 3- [N- (1-naphthyl) -N- (9-phenylcarbazole-3- Yl) amino] -9-phenylcarbazole (abbreviation: PCzPCN1) and the like. In addition, 4,4′-di (N-carbazolyl) biphenyl (abbreviation: CBP), 1,3,5-tris [4- (N-carbazolyl) phenyl] benzene (abbreviation: TCPB), 9- [4- ( Carbazole derivatives such as 10-phenyl-9-anthracenyl) phenyl] -9H-carbazole (abbreviation: CzPA), and the like can be used. The substances described here are mainly substances having a hole mobility of 1 × 10 ⁻⁶ cm ² / Vs or higher. Note that other than these substances, any substance that has a property of transporting more holes than electrons may be used.

  Further, poly (N-vinylcarbazole) (abbreviation: PVK), poly (4-vinyltriphenylamine) (abbreviation: PVTPA), poly [N- (4- {N ′-[4- (4-diphenylamino)] Phenyl] phenyl-N′-phenylamino} phenyl) methacrylamide] (abbreviation: PTPDMA), poly [N, N′-bis (4-butylphenyl) -N, N′-bis (phenyl) benzidine] (abbreviation: Polymer compounds such as Poly-TPD can also be used.

An acceptor substance used for the hole-injection layer 111 and the hole-injection layer 116 is 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation: F ₄ − Electron withdrawing groups (halogen groups, chloroanyl, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviation: HAT-CN)) And compounds having a cyano group. Moreover, a transition metal oxide can be mentioned. In addition, oxides of metals belonging to Groups 4 to 8 in the periodic table can be given. Specifically, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide, manganese oxide, and rhenium oxide are preferable because of their high electron accepting properties. Among these, molybdenum oxide is particularly preferable because it is stable in the air, has a low hygroscopic property, and is easy to handle. Note that the hole-injection layer 111 and the hole-injection layer 116 may be formed using an acceptor substance alone or mixed with another material.

≪Hole transport layer≫
The hole-transport layer 112 and the hole-transport layer 117 are layers including a material having a hole-transport property (hole-transport material), and the materials exemplified as the material of the hole-injection layer 111 and the hole-injection layer 116 are used. Can be used. Since the hole transport layer 112 has a function of transporting holes injected into the hole injection layer 111 to the light emitting layer 121, the highest occupied orbit (also referred to as Highest Occupied Molecular Orbital, HOMO) of the hole injection layer 111 is included. It is preferable to have a HOMO energy level that is the same as or close to the position.

  As a material having a hole transporting property, 4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (abbreviation: NPB), N, N′-bis (3-methylphenyl)- N, N′-diphenyl- [1,1′-biphenyl] -4,4′-diamine (abbreviation: TPD), 4,4′-bis [N- (spiro-9,9′-bifluoren-2-yl) ) -N-phenylamino] biphenyl (abbreviation: BSPB), 4-phenyl-4 '-(9-phenylfluoren-9-yl) triphenylamine (abbreviation: BPAFLP), 4-phenyl-3'-(9- Phenylfluoren-9-yl) triphenylamine (abbreviation: mBPAFLP), 4-phenyl-4 ′-(9-phenyl-9H-carbazol-3-yl) triphenylamine (abbreviation: PCBA1BP), 4 4′-diphenyl-4 ″-(9-phenyl-9H-carbazol-3-yl) triphenylamine (abbreviation: PCBBi1BP), 4- (1-naphthyl) -4 ′-(9-phenyl-9H-carbazole) -3-yl) triphenylamine (abbreviation: PCBBANB), 4,4′-di (1-naphthyl) -4 ″-(9-phenyl-9H-carbazol-3-yl) triphenylamine (abbreviation: PCBNBB) ), 9,9-dimethyl-N-phenyl-N- [4- (9-phenyl-9H-carbazol-3-yl) phenyl] fluoren-2-amine (abbreviation: PCBAF), N-phenyl-N- [ Aromatic amines such as 4- (9-phenyl-9H-carbazol-3-yl) phenyl] spiro-9,9′-bifluoren-2-amine (abbreviation: PCBASF) Compounds having a rating, 1,3-bis (N-carbazolyl) benzene (abbreviation: mCP), 4,4′-di (N-carbazolyl) biphenyl (abbreviation: CBP), 3,6-bis (3,5 -Diphenylphenyl) -9-phenylcarbazole (abbreviation: CzTP), 3,3′-bis (9-phenyl-9H-carbazole) (abbreviation: PCCP) and other compounds having a carbazole skeleton, and 4,4 ′, 4 ''-(Benzene-1,3,5-triyl) tri (dibenzothiophene) (abbreviation: DBT3P-II), 2,8-diphenyl-4- [4- (9-phenyl-9H-fluoren-9-yl) ) Phenyl] dibenzothiophene (abbreviation: DBTFLP-III), 4- [4- (9-phenyl-9H-fluoren-9-yl) phenyl] -6-phenyldibenzothiop A compound having a thiophene skeleton such as phen (abbreviation: DBTFLP-IV), 4,4 ′, 4 ″-(benzene-1,3,5-triyl) tri (dibenzofuran) (abbreviation: DBF3P-II), And a compound having a furan skeleton such as 4- {3- [3- (9-phenyl-9H-fluoren-9-yl) phenyl] phenyl} dibenzofuran (abbreviation: mmDBFFLBi-II). Among the compounds described above, a compound having an aromatic amine skeleton and a compound having a carbazole skeleton are preferable because they have good reliability, high hole transportability, and contribute to reduction in driving voltage. In addition to the hole transporting material described above, a hole transporting material may be used from various substances.

  Further, as a substance having a high hole-transport property, for example, 3- [4- (1-naphthyl) -phenyl] -9-phenyl-9H-carbazole (abbreviation: PCPN), 3- [4- (9-phenanthryl) -Phenyl] -9-phenyl-9H-carbazole (abbreviation: PCPPn), 4-phenyl-4 ′-(9-phenyl-9H-carbazol-3-yl) triphenylamine (abbreviation: PCBA1BP), 4, 4 ′ -Di (1-naphthyl) -4 ''-(9-phenyl-9H-carbazol-3-yl) triphenylamine (abbreviation: PCBNBB), 4-phenyldiphenyl- (9-phenyl-9H-carbazole-3- Yl) amine (abbreviation: PCA1BP), 3,3′-bis (9-phenyl-9H-carbazole) (abbreviation: PCCP), N- [4- (9H-carba) -9-yl) phenyl] -N- (4-phenyl) phenylaniline (abbreviation: YGA1BP), 1,3,5-tri (dibenzothiophen-4-yl) -benzene (abbreviation: DBT3P-II), 4,4 ′, 4 ″-(benzene-1,3,5-triyl) tri (dibenzofuran) (abbreviation: DBF3P-II), 4-phenyl-4 ′-(9-phenylfluoren-9-yl) tri Phenylamine (abbreviation: BPAFLP), 4- [3- (triphenylene-2-yl) phenyl] dibenzothiophene (abbreviation: mDBTPTp-II), 4,4′-bis [N- (1-naphthyl) -N-phenyl Amino] biphenyl (abbreviation: NPB or α-NPD) and N, N′-bis (3-methylphenyl) -N, N′-diphenyl- [1,1′-biphenyl] -4,4 '-Diamine (abbreviation: TPD), 4,4', 4 "-tris (carbazol-9-yl) triphenylamine (abbreviation: TCTA), 4,4 ', 4" -tris (N, N- Diphenylamino) triphenylamine (abbreviation: TDATA), 4,4 ′, 4 ″ -tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine (abbreviation: MTDATA), 4,4 ′ A compound having an aromatic amine skeleton such as -bis [N- (spiro-9,9'-bifluoren-2-yl) -N-phenylamino] biphenyl (abbreviation: BSPB), 3- [N- (9-phenyl) Carbazol-3-yl) -N-phenylamino] -9-phenylcarbazole (abbreviation: PCzPCA1), 3,6-bis [N- (9-phenylcarbazol-3-yl) -N-Fe Ruamino] -9-phenylcarbazole (abbreviation: PCzPCA2), 3- [N- (1-naphthyl) -N- (9-phenylcarbazol-3-yl) amino] -9-phenylcarbazole (abbreviation: PCzPCN1), and the like. Can be mentioned. Other carbazole compounds and amine compounds such as 4,4′-di (N-carbazolyl) biphenyl (abbreviation: CBP), 1,3,5-tris [4- (N-carbazolyl) phenyl] benzene (abbreviation: TCPB) , Dibenzothiophene compounds, dibenzofuran compounds, fluorene compounds, triphenylene compounds, phenanthrene compounds, and the like can be used.

  In addition, you may use the compound which can be used as these positive hole transport layers as a positive hole injection layer.

≪Electron transport layer≫
The electron transport layer 113 and the electron transport layer 118 are layers containing a substance having a high electron transport property. Examples of materials used for the electron transport layer 113 and the electron transport layer 118 include metal complexes having a quinoline ligand, a benzoquinoline ligand, an oxazole ligand, or a thiazole ligand, an oxadiazole derivative, a triazole derivative, and phenanthroline. Derivatives, pyridine derivatives, bipyridine derivatives and the like. Specifically, Alq ₃ , tris (4-methyl-8-quinolinolato) aluminum (III) (abbreviation: Almq ₃ ), bis (10-hydroxybenzo [h] quinolinato) beryllium (II) (abbreviation: BeBq ₂ ) , BAlq, Zn (BOX) ₂ , bis [2- (2-hydroxyphenyl) benzothiazolate] zinc (II) (abbreviation: Zn (BTZ) ₂ ), and the like can be used. 2- (4-biphenylyl) -5- (4-tert-butylphenyl) -1,3,4-oxadiazole (abbreviation: PBD), 1,3-bis [5- (p-tert-butyl) Phenyl) -1,3,4-oxadiazol-2-yl] benzene (abbreviation: OXD-7), 3- (4-tert-butylphenyl) -4-phenyl-5- (4-biphenylyl) -1 , 2,4-triazole (abbreviation: TAZ), 3- (4-tert-butylphenyl) -4- (4-ethylphenyl) -5- (4-biphenylyl) -1,2,4-triazole (abbreviation: p-EtTAZ), bathophenanthroline (abbreviation: Bphen), bathocuproin (abbreviation: BCP), 4,4′-bis (5-methylbenzoxazol-2-yl) stilbene (abbreviation: BzOs), etc. Heteroaromatic compounds can also be used. In addition, poly (2,5-pyridinediyl) (abbreviation: PPy), poly [(9,9-dihexylfluorene-2,7-diyl) -co- (pyridine-3,5-diyl)] (abbreviation: PF -Py), poly [(9,9-dioctylfluorene-2,7-diyl) -co- (2,2′-bipyridine-6,6′-diyl)] (abbreviation: PF-BPy) Molecular compounds can also be used. The substances mentioned here are mainly substances having an electron mobility of 1 × 10 ⁻⁶ cm ² / Vs or higher. Note that other than the above substances, any substance that has a property of transporting more electrons than holes may be used for the electron-transport layer 113 and the electron-transport layer 118.

  Further, the electron-transport layer 113 and the electron-transport layer 118 are not limited to a single layer, and two or more layers including any of the above substances may be stacked.

≪Electron injection layer≫
The electron injection layer 114 and the electron injection layer 119 are layers containing a substance having a high electron injection property. The electron injection layer 114 includes an alkali metal such as lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF ₂ ), lithium oxide (LiO _x ), an alkaline earth metal, or the like These compounds can be used. Alternatively, a rare earth metal compound such as erbium fluoride (ErF ₃ ) can be used. Further, electride may be used for the electron injection layer 114 and the electron injection layer 119. Examples of the electride include a substance obtained by adding a high concentration of electrons to a mixed oxide of calcium and aluminum. Alternatively, a substance that can be used for the electron transport layer 113 and the electron transport layer 118 may be used for the electron injection layer 114 and the electron injection layer 119.

  Alternatively, a composite material in which an organic compound and an electron donor (donor) are mixed may be used for the electron injection layer 114 and the electron injection layer 119. Such a composite material is excellent in electron injecting property and electron transporting property because electrons are generated in the organic compound by the electron donor. In this case, the organic compound is preferably a material that is excellent in transporting the generated electrons. Specifically, for example, a substance (metal complex or heteroaromatic material) that constitutes the electron transport layer 113 and the electron transport layer 118 described above, for example. Group compounds and the like). The electron donor may be any substance that exhibits an electron donating property to the organic compound. Specifically, alkali metals, alkaline earth metals, and rare earth metals are preferable, and lithium, cesium, magnesium, calcium, erbium, ytterbium, and the like can be given. Alkali metal oxides and alkaline earth metal oxides are preferable, and lithium oxide, calcium oxide, barium oxide, and the like can be given. A Lewis base such as magnesium oxide can also be used. Alternatively, an organic compound such as tetrathiafulvalene (abbreviation: TTF) can be used.

≪Charge generation layer≫
When a voltage is applied between the pair of electrodes (the electrode layer 101 and the electrode layer 102), the charge generation layer 115 injects electrons into one of the light emitting layers (the light emitting layer 121 or the light emitting layer 122) and emits the other light. It has a function of injecting holes into the layer (the light emitting layer 121 or the light emitting layer 122) side.

  For example, in the tandem light-emitting element 190 illustrated in FIG. 4, when a voltage is applied to the electrode layer 101 so that the potential is higher than that of the electrode layer 102, electrons are injected from the charge generation layer 115 to the light-emitting layer 121. Holes are injected into 122.

  Note that the charge generation layer 115 preferably has a property of transmitting visible light in terms of light extraction efficiency (specifically, the visible light transmittance of the charge generation layer 115 is 40% or more). Further, the charge generation layer 115 functions even when it has lower conductivity than the pair of electrodes (the electrode layer 101 and the electrode layer 102).

  In addition, the charge generation layer 115 may have a structure in which an electron acceptor is added to a hole transporting material or a structure in which an electron donor (donor) is added to an electron transporting material. Good. Moreover, both these structures may be laminated | stacked.

  Note that by forming the charge generation layer 115 using the above-described material, an increase in driving voltage when the light-emitting layer is stacked can be suppressed.

  Note that the light emitting layer, the hole transport layer, the hole injection layer, the electron transport layer, the electron injection layer, and the charge generation layer described above are vapor deposition methods (including vacuum vapor deposition methods), ink jet methods, coating methods, It can be formed by a method such as gravure printing. In addition, the light emitting layer, the hole transport layer, the hole injection layer, the electron transport layer, the electron injection layer, and the charge generation layer described above include an inorganic compound or a polymer compound (oligomer, dendrimer, A polymer or the like) may be used.

≪Optical element≫
The optical element 224R, the optical element 224G, and the optical element 224B selectively transmit light having a specific color from incident light. For example, a colored layer (also referred to as a color filter), a band pass filter, a multilayer filter, or the like can be used. Further, a color conversion element can be applied to the optical element. The color conversion element is an optical element that converts incident light into light having a wavelength longer than the wavelength of the light. The color conversion element is preferably an element using a quantum dot method. By using the quantum dot method, the color reproducibility of the display device can be improved.

  Note that a plurality of optical elements may be overlaid on the optical element 224R, the optical element 224G, and the optical element 224B. As another optical element, for example, a circular deflecting plate or an antireflection film can be provided. If a circularly polarizing plate is provided on the side from which light emitted from the light emitting element of the display device is extracted, light incident from the outside of the display device is reflected inside the display device and prevented from being emitted to the outside. it can. In addition, when an antireflection film is provided, external light reflected on the surface of the display device can be weakened. Thereby, the light emission which a display apparatus emits can be observed clearly.

≪Shading layer≫
The light shielding layer 223 has a function of suppressing reflection of external light. Alternatively, the light-blocking layer 223 has a function of preventing color mixture of light emitted from adjacent light-emitting elements. As the light-blocking layer 223, a metal, a resin containing a black pigment, carbon black, a metal oxide, a composite oxide containing a solid solution of a plurality of metal oxides, or the like can be used.

≪Bulk wall≫
The partition 140 only needs to be insulative and is formed using an inorganic material or an organic material. Examples of the inorganic material include silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, aluminum oxide, and aluminum nitride. As this organic material, photosensitive resin materials, such as an acrylic resin or a polyimide resin, are mentioned, for example.

<9. Method for manufacturing light-emitting element>
Next, a method for manufacturing the light-emitting element of one embodiment of the present invention is described below with reference to FIGS. Note that here, a method for manufacturing the light-emitting element 290 illustrated in FIG. 7A will be described.

  9 and 10 are cross-sectional views illustrating a method for manufacturing a light-emitting element of one embodiment of the present invention.

  A method for manufacturing the light-emitting element 290 described below includes first to ninth nine steps.

≪First step≫
In the first step, an electrode layer of the light-emitting element (specifically, a conductive layer 101a constituting the electrode layer 101, a conductive layer 103a constituting the electrode layer 103, and a conductive layer 104a constituting the electrode layer 104) This is a step of forming over the substrate 200 (see FIG. 9A).

  In this embodiment, a reflective conductive layer is formed over the substrate 200, and the conductive layer is processed into a desired shape, so that the conductive layer 101a, the conductive layer 103a, and the conductive layer 104a are formed. As the reflective conductive layer, an alloy film of aluminum, nickel, and lanthanum (Al—Ni—La film) is used. As described above, it is preferable to form the conductive layer 101a, the conductive layer 103a, and the conductive layer 104a through the process of processing the same conductive layer because manufacturing costs can be reduced.

  Note that a plurality of transistors may be formed over the substrate 200 before the first step. The plurality of transistors may be electrically connected to the conductive layer 101a, the conductive layer 103a, and the conductive layer 104a.

≪Second step≫
The second step is a step of forming the oxide layer 101b over the conductive layer 101a included in the electrode layer 101 (see FIG. 9B).

  In this embodiment, an In—Ga—Zn oxide is used as the oxide layer 101b, and the composition of In: Ga: Zn is 1: 3: 6. In this manner, by setting the Ga content to be equal to or higher than the In content, the exchange of electrons and the exchange of oxygen between the conductive layer 101a and the oxide layer 101b can be suppressed, and the stable electrode layer 101 can be suppressed. It can be.

  Note that the same material may be used for the oxide layer 101b and the oxide semiconductor layer used for the channel region of the transistor which is formed in advance. By doing so, the oxide layer 101b can be formed without increasing the types of materials to be formed, and the manufacturing cost can be reduced. In that case, it is preferable that the film formation process be different between the oxide layer 101b and the oxide semiconductor layer used for the channel region of the transistor.

≪Third step≫
The third step is a step of forming an oxide layer 103b in contact with the conductive layer 103a constituting the electrode layer 103 and an oxide layer 104b in contact with the conductive layer 104a constituting the electrode layer 104 (FIG. 9 ( C)).

  In this embodiment, a titanium oxide layer obtained by baking Ti is used as the oxide layer 103b and the oxide layer 104b. In this manner, by using an oxide different from the oxide layer 101b for the oxide layer 103b and the oxide layer 104b, the electrode layer 103, the electrode layer 104, and the electrode layer 101 each have a hole for the EL layer. The injectability can be different.

≪Fourth Step≫
The fourth step is a step of forming a transparent conductive film (specifically, a transparent conductive film 101c constituting the electrode layer 101 and a transparent conductive film 103c constituting the electrode layer 103) of the light emitting element (FIG. 9 (D)).

  In this embodiment, the transparent conductive film 101c and the transparent conductive film 103c are formed over the oxide layer 101b and the oxide layer 103b, and the transparent conductive film is formed in the second step and the third step. The oxide layer is processed into a desired shape, whereby the electrode layer 101, the electrode layer 103, and the electrode layer 104 are formed. An ITSO film is used as the transparent conductive film 101c and the transparent conductive film 103c.

  Note that the transparent conductive film 101c and the transparent conductive film 103c may be formed in multiple steps. By forming in multiple steps, the transparent conductive film 101c and the transparent conductive film 103c can be formed with a film thickness that provides a suitable microcavity structure in each region.

≪Fifth step≫
The fifth step is a step of forming a partition 140 that covers an end portion of each electrode layer of the light emitting element (see FIG. 9E).

  The partition 140 has an opening so as to overlap with the electrode layer. The transparent conductive film or the oxide layer exposed through the opening functions as an anode of the light emitting element. In this embodiment, polyimide resin is used for the partition wall 140.

  Note that in the first to fifth steps, there is no possibility of damaging the EL layer (a layer containing an organic compound), and thus various film formation methods and microfabrication techniques can be applied. In this embodiment mode, a reflective conductive layer is formed using a sputtering method, the conductive layer is patterned using a lithography method, and then the conductive layer is formed using a dry etching method or a wet etching method. Is processed into an island shape, thereby forming a conductive layer 101a constituting the electrode layer 101, a conductive layer 103a constituting the electrode layer 103, and a conductive layer 104a constituting the electrode layer 104. Thereafter, an oxide layer and a transparent conductive film are formed using a sputtering method, a pattern is formed on the oxide layer and the transparent conductive film using a lithography method, and then the oxidation is performed using a wet etching method. The physical layer and the transparent conductive film are processed into an island shape to form the electrode layer 101, the electrode layer 103, and the electrode layer 104.

≪Sixth Step≫
The sixth step is a step of forming the hole injection layer 111, the hole transport layer 112, the light emitting layer 121, the electron transport layer 113, the electron injection layer 114, and the charge generation layer 115 (see FIG. 10A). ).

  The hole injection layer 111 can be formed by co-evaporation of a hole transporting material and a material containing an acceptor substance. Note that co-evaporation is an evaporation method in which a plurality of different substances are simultaneously evaporated from different evaporation sources. The hole transport layer 112 can be formed by vapor deposition of a hole transport material.

  The light emitting layer 121 can be formed by vapor-depositing a second compound that emits at least one selected from green, yellowish green, yellow, orange, and red. As the second compound, a phosphorescent organic compound can be used. The phosphorescent organic compound may be vapor-deposited alone, or may be vapor-deposited by mixing with other materials. For example, a phosphorescent organic compound may be used as a guest material, and the guest material may be dispersed and deposited in a host material having higher excitation energy than the guest material. The light-emitting layer 121 preferably has a two-layer structure of a light-emitting layer 121a and a light-emitting layer 121b. In that case, the light-emitting layer 121a and the light-emitting layer 121b each preferably include a light-emitting substance that exhibits different emission colors.

  The electron transport layer 113 can be formed by evaporating a substance having a high electron transport property. Further, the electron injection layer 114 can be formed by vapor deposition of a substance having a high electron injection property.

  The charge generation layer 115 is formed by vapor-depositing a material in which an electron acceptor (acceptor) is added to a hole transporting material, or a material in which an electron donor (donor) is added to an electron transporting material. Can do.

≪Seventh Step≫
The seventh step is a step of forming the hole injection layer 116, the hole transport layer 117, the light emitting layer 122, the electron transport layer 118, the electron injection layer 119, and the electrode layer 102 (see FIG. 10B). .

  The hole injection layer 116 can be formed using the same material and the same method as those of the hole injection layer 111 described above. Further, the hole transport layer 117 can be formed using a material and a method similar to those of the hole transport layer 112 described above.

  The light emitting layer 122 can be formed by vapor-depositing a first compound that emits at least one selected from purple, blue, and blue-green. As the first compound, a fluorescent organic compound can be used. The fluorescent organic compound may be vapor-deposited alone, or may be vapor-deposited by mixing with other materials. For example, a fluorescent organic compound may be used as a guest material, and the guest material may be dispersed and deposited on a host material having excitation energy higher than that of the guest material.

  The electron transport layer 118 can be formed by vapor deposition of a substance having a high electron transport property. Further, the electron injection layer 119 can be formed by vapor-depositing a substance having a high electron injection property.

  The electrode layer 102 can be formed by stacking a reflective conductive film and a light-transmitting conductive film. Further, the electrode layer 102 may have a single-layer structure or a stacked structure.

  Through the above steps, a light-emitting element having a region 221R, a region 221G, and a region 221B is formed over the substrate 200 over the electrode layer 101, the electrode layer 103, and the electrode layer 104, respectively.

≪Eighth step≫
The eighth step is a step of forming the light shielding layer 223, the optical element 224R, the optical element 224G, and the optical element 224B over the substrate 220 (see FIG. 10C).

  As the light shielding layer 223, a resin film containing a black pigment is formed in a desired region. After that, the optical element 224R, the optical element 224G, and the optical element 224B are formed over the substrate 220 and the light shielding layer 223. As the optical element 224R, a resin film containing a red pigment is formed in a desired region. As the optical element 224G, a resin film containing a green pigment is formed in a desired region. Further, as the optical element 224B, a resin film containing a blue pigment is formed in a desired region.

≪Ninth Step≫
In the ninth step, the light emitting element formed over the substrate 200 and the light shielding layer 223, the optical element 224R, the optical element 224G, and the optical element 224B formed over the substrate 220 are bonded together, and a sealing material is attached. It is the process of sealing using (not shown).

  Through the above steps, the light-emitting element 290 illustrated in FIG. 7A can be formed.

  Note that one embodiment of the present invention is described in this embodiment. Alternatively, in another embodiment, one embodiment of the present invention will be described. Note that one embodiment of the present invention is not limited thereto. For example, in one embodiment of the present invention, the oxide layer 101b in contact with the conductive layer 101a in the electrode layer 101 includes In and a stabilizer M (where M is Al, Si, Ti, Ga, Y, Zr, Sn, La, Ce). , Nd or Hf) and the content of M contained in the oxide layer 101b is greater than or equal to the content of In, but one embodiment of the present invention is limited to this. Not. Depending on circumstances or circumstances, in one embodiment of the present invention, for example, the oxide layer 101b includes In or a stabilizer M (where M is Al, Si, Ti, Ga, Y, Zr, Sn, La, Ce, Nd or Hf) may not be present. Alternatively, for example, the M content in the oxide layer 101b may not be greater than the In content. For example, in one embodiment of the present invention, the oxide layer 101b in contact with the conductive layer 101a in the electrode layer 101 and the oxide layer 103b in contact with the conductive layer 103a in the electrode layer 103 include different oxides. However, one embodiment of the present invention is not limited thereto. Depending on circumstances or conditions, in one embodiment of the present invention, for example, the oxide layer 101b and the oxide layer 103b may include the same oxide. Alternatively, for example, in one embodiment of the present invention, the oxide semiconductor layer in the channel region of the transistor that performs switching includes In and a stabilizer M (M is Al, Si, Ti, Ga, Y, Zr, Sn, La, and Ce). , Nd or Hf) is shown, but one embodiment of the present invention is not limited thereto. Depending on circumstances or circumstances, in one embodiment of the present invention, for example, the oxide semiconductor layer includes In or a stabilizer M (where M is Al, Si, Ti, Ga, Y, Zr, Sn, La, Ce, Nd or Hf) may not be present. Alternatively, for example, in one embodiment of the present invention, the conductive layer 101a in the electrode layer 101 has a function of reflecting light; however, in one embodiment of the present invention, for example, the conductive layer 101a has a light reflecting function. It is not necessary to have a function of reflecting light. Alternatively, depending on circumstances or circumstances, in one embodiment of the present invention, for example, the electrode layer 101 may not include the oxide layer 101b.

  As described above, this embodiment can be combined with any of the other embodiments or examples as appropriate.

(Embodiment 2)
In this embodiment, a light-emitting mechanism of the light-emitting element which can be used for the light-emitting element of one embodiment of the present invention or the display device of one embodiment of the present invention will be described below with reference to FIGS.

  FIG. 11 is a schematic cross-sectional view of the light-emitting element 450.

  A light-emitting element 450 illustrated in FIG. 11 has a structure in which an EL layer 400 is sandwiched between a pair of electrodes (an electrode layer 401 and an electrode layer 402). Note that in the light-emitting element 450, the electrode layer 401 functions as an anode and the electrode layer 402 functions as a cathode; however, one embodiment of the present invention is not limited thereto.

  In addition, the EL layer 400 includes a light-emitting layer 413 and a light-emitting layer 414. In addition, in the light-emitting element 450, as the EL layer 400, in addition to the light-emitting layer 413 and the light-emitting layer 414, a hole injection layer 411, a hole transport layer 412, an electron transport layer 415, and an electron injection layer 416 are illustrated. However, these stacked structures are examples, and the structure of the EL layer 400 in the light-emitting element 450 is not limited thereto. For example, in the EL layer 400, the stacking order of the above layers may be changed. Alternatively, a functional layer other than the above layers may be provided in the EL layer 400. For example, the functional layer may have a function of injecting carriers (electrons or holes), a function of transporting carriers, a function of suppressing carriers, and a function of generating carriers.

  In addition, the light-emitting layer 413 includes a guest material 421 and a host material 422. The light-emitting layer 414 includes a guest material 431, an organic compound 432, and an organic compound 433. Note that the guest material 421 is a fluorescent material and the guest material 431 is a phosphorescent material.

<Light emitting mechanism of light emitting layer 413>
First, the light emission mechanism of the light emitting layer 413 will be described below.

  In the light-emitting layer 413, an excited state is formed by carrier recombination. Since the host material 422 is present in a large amount as compared with the guest material 421, the excited state exists almost as the excited state of the host material 422. The ratio between the singlet excited state and the triplet excited state (hereinafter, exciton generation probability) generated by carrier recombination is about 1: 3.

First, _{T 1} level of the host material 422 for the case higher than the _{T 1} level of the guest material 421, described below.

Energy transfer (triplet energy transfer) occurs from the triplet excitation energy level of the host material 422 to the triplet excitation energy level of the guest material 421. However, since the guest material 421 is a fluorescent material, it does not emit light in the visible light region when the guest material 421 is in a triplet excited state. Therefore, it is difficult to use the triplet excited state energy of the host material 422 as light emission. Therefore, when the T ₁ level of the host material 422 is higher than the T ₁ level of the guest material 421, it is difficult to use more than 25% of the injected carriers for light emission.

Next, FIG. 12A shows the correlation of energy levels between the host material 422 and the guest material 421 in the light-emitting layer 413. In addition, the notation and code | symbol in FIG. 12 (A) are as follows.
Host (422): Host material 422
Guest (421): Guest material 421 (fluorescent material)
S _FH : lowest level of singlet excited state of host material 422 T _FH : lowest level of triplet excited state of host material 422 S _FG : singlet excited state of guest material 421 (fluorescent material) The lowest level of T _FG : The lowest level of the triplet excited state of the guest material 421 (fluorescent material)

As shown in FIG. 12A, the T ₁ level of the guest material (T _FG in FIG. 12A) is higher than the T ₁ level of the host material (T _FH in FIG. 12A). It is a configuration.

Further, as shown in FIG. 12A, triplet-triplet annihilation (TTA) causes triplet excitons to collide with each other, so that part of the excitation energy of the host material is reduced. It is converted to the lowest level (S _FH ) of the singlet excited state. Energy transfer from the lowest level (S _FH ) in the singlet excited state of the host material to the lowest level (S _FG ) in the singlet excited state of the guest material (fluorescent material) having a lower level than that. Occurs (see Route A in FIG. 12A), and the guest material (fluorescent material) emits light.

Note that since the T ₁ level of the host material is lower than the T ₁ level of the guest material, T _FG transfers energy to T _FH without deactivation (see Route B shown in FIG. 12A), and TTA Used for

  When the light-emitting layer 413 has the above structure, light emission from the guest material 421 of the light-emitting layer 413 can be efficiently obtained.

<Light emitting mechanism of light emitting layer 414>
Next, the light emission mechanism of the light emitting layer 414 will be described below.

  The organic compound 432 and the organic compound 433 included in the light-emitting layer 414 form an exciplex (also referred to as an exciplex). One of the organic compound 432 and the organic compound 433 functions as a host material for the light-emitting layer 414, and the other of the organic compound 432 and the organic compound 433 functions as an assist material for the light-emitting layer 414. In the following description, the organic compound 432 is used as a host material and the organic compound 433 is used as an assist material.

  The combination of the organic compound 432 and the organic compound 433 may be a combination that can form an exciplex in the light-emitting layer 414, but one is a material having a hole transporting property and the other has an electron transporting property. It is more preferable that the material has. In this case, it becomes easy to form a donor-acceptor type excited state, and an excited complex can be formed efficiently. In the case where the combination of the organic compound 432 and the organic compound 433 is configured by a combination of a material having a hole transporting property and a material having an electron transporting property, the carrier balance can be easily controlled by the mixing ratio. Specifically, a material having a hole transporting property: a material having an electron transporting property = 1: 9 to 9: 1 (weight ratio) is preferable. In addition, since the carrier balance can be easily controlled by having this configuration, the recombination region can be easily controlled.

FIG. 12B shows the correlation of energy levels among the organic compound 432, the organic compound 433, and the guest material 431 in the light-emitting layer 414. In addition, the notation and code | symbol in FIG. 12 (B) are as follows.
Host (432): Host material (organic compound 432)
Assist (433): Assist material (organic compound 433)
Guest (431): Guest material 431 (phosphorescent material)
・ Exciplex: exciplex (organic compound 432 and organic compound 433)
_SPH : lowest level of singlet excited state of host material (organic compound 432) _TPH : lowest level of triplet excited state of host material (organic compound 432) _TPG : guest material 431 ( Lowest level of triplet excited state of phosphorescent material) S _E : lowest level of singlet excited state of exciplex • T _E : lowest level of triplet excited state of exciplex

In the light-emitting element of one embodiment of the present invention, the organic compound 432 and the organic compound 433 included in the light-emitting layer 414 form an exciplex. The lowest level (S _E ) of the singlet excited state of the exciplex and the lowest level (T _E ) of the triplet excited state of the exciplex are adjacent to each other (see FIG. 12 (B) Route C). .

The exciplex is an excited state composed of two kinds of substances. In the case of photoexcitation, one excited substance interacts with another substance in the ground state. And if it will be in a ground state by emitting light, the two types of substances that have formed the exciplex will also behave as separate original substances. In the case of electrical excitation, an exciplex can be formed by the proximity of one cationic substance and the other anionic substance. That is, in electrical excitation, an exciplex can be formed without forming an excited state in any substance, leading to a reduction in driving voltage. Then, the energy of both (S _E ) and (T _E ) of the exciplex is transferred to the lowest level of the triplet excited state of the guest material 431 (phosphorescent material), and light emission is obtained (FIG. 12B ) See Route D).

  Note that the process of Route C and Route D described above may be referred to as ExTET (Exciplex-Triple Energy Transfer) in this specification and the like. In other words, the light-emitting element 450 has energy supply from the exciplex to the guest material 431 (phosphorescent material).

  Further, one of the organic compound 432 and the organic compound 433 receives a hole, the other receives an electron, and an organic compound 432 and an organic compound 433 quickly form an exciplex when these organic compounds come close to each other. Alternatively, when one is in an excited state, it rapidly interacts with the other substance to form an exciplex. Therefore, most excitons in the light-emitting layer 414 exist as exciplexes. Since the exciplex has a smaller band gap than both the organic compound 432 and the organic compound 433, a driving voltage can be lowered by forming an exciplex from recombination of one hole and the other electron.

  When the light-emitting layer 414 has the above structure, light emission from the guest material 431 (phosphorescent material) of the light-emitting layer 414 can be efficiently obtained.

<Light emitting mechanism of light emitting layer 413 and light emitting layer 414>
The light emitting mechanisms of the light emitting layer 413 and the light emitting layer 414 have been described above. When the light emitting layer 413 and the light emitting layer 414 are in contact with each other as shown in the light emitting element 450, the light emitting layer 413 and the light emitting layer are provided. Even if energy transfer from the exciplex to the host material 422 of the light-emitting layer 413 occurs (especially energy transfer of triplet excited level) at the interface of 414, the triplet excitation energy is converted into light emission in the light-emitting layer 413. can do.

Incidentally, _{T 1} level of the host material 422 of the light emitting layer 413, preferably lower than _{T 1} level of an organic compound 432 and the organic compound 433 emitting layer 414 has. In the light-emitting layer 413, _{S 1} level of the host material 422 is higher than the _{S 1} level of the guest material 421 (a fluorescent material), and, _{T 1} level of the host material 422 guest material 421 (fluorescent material) Is preferably lower than the T ₁ level.

Specifically, FIG. 13 shows the correlation of energy levels when TTA is used for the light emitting layer 413 and ExTET is used for the light emitting layer 414. In addition, the description and code | symbol in FIG. 13 are as follows.
Fluorescence EML (413): fluorescent light emitting layer (light emitting layer 413)
Phosphorescence EML (414): phosphorescent light emitting layer (light emitting layer 414)
S _FH : lowest level of singlet excited state of host material 422 T _FH : lowest level of triplet excited state of host material 422 S _FG : singlet excited state of guest material 421 (fluorescent material) T _FG : lowest level of triplet excited state of guest material 421 (fluorescent material) • S _PH : lowest level of singlet excited state of host material (organic compound 432) • T _PH : the lowest level · T _PG triplet excited state of the host material (organic compound _432): guest material 431 lowest level · S _E triplet excited state of (phosphorescent _material): singlet excited state of the exciplex Lowest level of T _E : lowest level of triplet excited state of exciplex

As shown in FIG. 13, since the exciplex exists only in an excited state, exciton diffusion between the exciplex and the exciplex is unlikely to occur. Further, since the excitation level (S _E , T _E ) of the exciplex is lower than the excitation level (S _PH , T _PH ) of the organic compound 432 (that is, the host material of the phosphorescent material) in the light-emitting layer 414, excitation is performed. Energy diffusion from the complex to the organic compound 432 does not occur. That is, since the exciton diffusion distance of the exciplex is short in the phosphorescent light emitting layer (light emitting layer 414), the efficiency of the phosphorescent light emitting layer (light emitting layer 414) can be maintained. In addition, at the interface between the fluorescent light-emitting layer (light-emitting layer 413) and the phosphorescent light-emitting layer (light-emitting layer 414), part of the triplet excitation energy of the exciplex of the phosphorescent light-emitting layer (light-emitting layer 414) is Even if it diffuses to 413), the triplet excitation energy of the fluorescent light-emitting layer (light-emitting layer 413) generated by the diffusion is emitted through TTA, so that energy loss can be reduced.

  As described above, the light-emitting element 450 can have high light-emitting efficiency because energy loss is reduced by using ExTET for the light-emitting layer 414 and TTA for the light-emitting layer 413. . In the case where the light-emitting layer 413 and the light-emitting layer 414 are in contact with each other as illustrated in the light-emitting element 450, the energy loss is reduced and the number of layers of the EL layer 400 can be reduced. Therefore, a light-emitting element with low manufacturing cost can be obtained.

  Note that the light-emitting layer 413 and the light-emitting layer 414 may not be in contact with each other. In this case, energy from the excited state of the organic compound 432 or the guest material 431 (phosphorescent material) generated in the light-emitting layer 414 to the host material 422 or the guest material 421 (fluorescent material) in the light-emitting layer 413 by the Dexter mechanism. Transfer (especially triplet energy transfer) can be prevented. Therefore, the layer provided between the light-emitting layer 413 and the light-emitting layer 414 may have a thickness of about several nm.

  The layer provided between the light-emitting layer 413 and the light-emitting layer 414 may be formed of a single material, but may include both a hole transporting material and an electron transporting material. In the case of a single material, a bipolar material may be used. Here, the bipolar material refers to a material having a mobility ratio of electrons and holes of 100 or less. Further, a hole transporting material or an electron transporting material may be used. Alternatively, at least one of them may be formed using the same material as the host material (organic compound 432) of the light-emitting layer 414. This facilitates the production of the light emitting element and reduces the driving voltage. Further, an exciplex may be formed by the hole transporting material and the electron transporting material, thereby effectively preventing exciton diffusion. Specifically, energy transfer from the excited state of the host material (organic compound 432) or the guest material 431 (phosphorescent material) of the light-emitting layer 414 to the host material 422 or the guest material 421 (fluorescent material) of the light-emitting layer 413 is prevented. be able to.

  Note that in the light-emitting element 450, the carrier recombination region is preferably formed with a certain distribution. Therefore, the light-emitting layer 413 or the light-emitting layer 414 preferably has an appropriate carrier trapping property. In particular, the guest material 431 (phosphorescent material) included in the light-emitting layer 414 preferably has an electron-trapping property. Alternatively, the guest material 421 (fluorescent material) included in the light-emitting layer 413 preferably has a hole-trapping property.

  Note that a structure in which light emission from the light-emitting layer 413 has a light emission peak on a shorter wavelength side than light emission from the light-emitting layer 414 is preferable. A light-emitting element using a phosphorescent material that emits light having a short wavelength tends to deteriorate in luminance. Therefore, a light-emitting element with small luminance deterioration can be provided by using short-wavelength light emission as fluorescent light emission.

  In addition, by obtaining light with different emission wavelengths in the light-emitting layer 413 and the light-emitting layer 414, a multicolor light-emitting element can be obtained. In this case, since the emission spectrum is light in which emission having different emission peaks is synthesized, it becomes an emission spectrum having at least two maximum values.

  The above configuration is also suitable for obtaining white light emission. White light emission can be obtained by making the light of the light emitting layer 413 and the light emitting layer 414 have complementary colors.

  In addition, by using a plurality of light-emitting substances having different emission wavelengths for the light-emitting layer 413, white light emission with high color rendering properties composed of three primary colors or four or more emission colors can be obtained. In this case, the light emitting layer 413 may be further divided into layers, and a different light emitting material may be included in each of the divided layers.

  Therefore, a light-emitting element having high light emission efficiency can be manufactured by combining the above structure with the electrode layer structure described in Embodiment Mode 1. That is, like the electrode layer 101, the electrode layer 401 includes the conductive layer 401a and the oxide layer 401b, so that the electrode layer 401 has a high reflectance and is a stable electrode layer. Therefore, a light-emitting element having high light emission efficiency can be manufactured.

  In addition, by using the above structure for the light-emitting element having a plurality of different electrode layer structures in the subpixels described in Embodiment Mode 1, that is, the electrode layer 401 has the same structure as the electrode layer 101, and the electrode layer By using a structure similar to that of the electrode layer 102 for the light-emitting element 402, the light-emitting element including the electrode layer 401 and the electrode layer 402 has high emission intensity of one of the light-emitting layer 413 and the light-emitting layer 414, and is similar to the electrode layer 103. In a light-emitting element having an electrode layer having an electrode structure different from that of the electrode layer 401 and the electrode layer 402, the light emission intensity of the other of the light-emitting layer 413 or the light-emitting layer 414 can be increased. That is, by using the electrode layer of one embodiment of the present invention, different emission colors can be extracted from each subpixel without separately coating the EL layer. Therefore, a display device with high light use efficiency can be manufactured without reducing yield. That is, a display device with low power consumption can be manufactured. In addition, the manufacturing cost of the display device can be reduced.

  Next, materials that can be used for the light-emitting layer 413 and the light-emitting layer 414 are described below.

<Materials that can be used for the light-emitting layer 413>
In the light emitting layer 413, the host material 422 is present in the largest amount by weight, and the guest material 421 (fluorescent material) is dispersed in the host material 422. _{S 1} level of the host material 422 is higher than the _{S 1} level of the guest material 421 (a fluorescent material), _{T 1} level of the host material 422, than _{T 1} level of the guest material 421 (fluorescent material) Preferably it is low.

As the host material 422, an anthracene derivative or a tetracene derivative is preferable. This is because these derivatives have a high S ₁ level and a low T ₁ level. Specifically, 9-phenyl-3- [4- (10-phenyl-9-anthryl) phenyl] -9H-carbazole (abbreviation: PCzPA), 3- [4- (1-naphthyl) -phenyl] -9 -Phenyl-9H-carbazole (abbreviation: PCPN), 9- [4- (10-phenyl-9-anthracenyl) phenyl] -9H-carbazole (abbreviation: CzPA), 7- [4- (10-phenyl-9- Anthryl) phenyl] -7H-dibenzo [c, g] carbazole (abbreviation: cgDBCzPA), 6- [3- (9,10-diphenyl-2-anthryl) phenyl] -benzo [b] naphtho [1,2-d ] Furan (abbreviation: 2 mBnfPPA), 9-phenyl-10- {4- (9-phenyl-9H-fluoren-9-yl) biphenyl-4'-yl} anthracene ( (Abbreviation: FLPPA). Alternatively, 5,12-diphenyltetracene, 5,12-bis (biphenyl-2-yl) tetracene, and the like can be given.

  As guest materials 421 (fluorescent materials), pyrene derivatives, anthracene derivatives, triphenylene derivatives, fluorene derivatives, carbazole derivatives, dibenzothiophene derivatives, dibenzofuran derivatives, dibenzoquinoxaline derivatives, quinoxaline derivatives, pyridine derivatives, pyrimidine derivatives, phenanthrene derivatives, naphthalene derivatives Etc. In particular, a pyrene derivative is preferable because of its high emission quantum yield. Specific examples of the pyrene derivative include N, N′-bis (3-methylphenyl) -N, N′-bis [3- (9-phenyl-9H-fluoren-9-yl) phenyl] pyrene-1,6. -Diamine (abbreviation: 1,6 mM emFLPAPrn), N, N'-diphenyl-N, N'-bis [4- (9-phenyl-9H-fluoren-9-yl) phenyl] pyrene-1,6-diamine (abbreviation) : 1,6FLPAPrn), N, N′-bis (dibenzofuran-2-yl) -N, N′-diphenylpyrene-1,6-diamine (abbreviation: 1,6FrAPrn), N, N′-bis (dibenzothiophene) -2-yl) -N, N′-diphenylpyrene-1,6-diamine (abbreviation: 1,6ThAPrn) and the like.

<Material that can be used for light-emitting layer 414>
In the light emitting layer 414, the host material (organic compound 432) is present in the largest amount by weight ratio, and the guest material 431 (phosphorescent material) is dispersed in the host material (organic compound 432). The T ₁ level of the host material (organic compound 432) of the light-emitting layer 414 is preferably higher than the T ₁ level of the guest material 421 (fluorescent material) of the light-emitting layer 413, and the guest material 431 (phosphorescence of the light-emitting layer 414) It is preferably higher than the T ₁ level of the material.

  As host materials (organic compounds 432), in addition to zinc and aluminum-based metal complexes, oxadiazole derivatives, triazole derivatives, benzimidazole derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives, dibenzothiophene derivatives, dibenzofuran derivatives, pyrimidine derivatives, triazine derivatives Pyridine derivatives, bipyridine derivatives, phenanthroline derivatives and the like. Other examples include aromatic amines and carbazole derivatives.

  Examples of the guest material 431 (phosphorescent material) include iridium, rhodium, or platinum-based organometallic complexes, or metal complexes. Among these, organic iridium complexes such as iridium-based orthometal complexes are preferable. Examples of orthometalated ligands include 4H-triazole ligands, 1H-triazole ligands, imidazole ligands, pyridine ligands, pyrimidine ligands, pyrazine ligands, and isoquinoline ligands. Can be mentioned. Examples of the metal complex include a platinum complex having a porphyrin ligand.

  The organic compound 433 (assist material) is a combination that can form an exciplex with the organic compound 432. In this case, the organic compound 432 and the organic compound are arranged so that the emission peak of the exciplex overlaps with the absorption band of the triplet MLCT (Metal to Ligand Charge Transfer) transition of the phosphorescent material, more specifically, the absorption band on the longest wavelength side. It is preferable to select 433 and the guest material 431 (phosphorescent material). Thereby, it can be set as the light emitting element which luminous efficiency improved greatly. However, in the case where a thermally activated delayed fluorescence (TADF) material is used instead of the phosphorescent material, it is preferable that the absorption band on the longest wavelength side is a singlet absorption band.

  The light-emitting material included in the light-emitting layer 414 may be any material that can convert triplet excitation energy into light emission. As a material capable of converting the triplet excitation energy into light emission, a TADF material can be cited in addition to a phosphorescent material. Therefore, the portion described as phosphorescent material may be read as TADF material. A TADF material is a material that can up-convert a triplet excited state to a singlet excited state with a slight amount of thermal energy (interverse crossing) and efficiently emits light (fluorescence) from the singlet excited state. That is. As a condition for efficiently obtaining thermally activated delayed fluorescence, the energy difference between the triplet excited level and the singlet excited level is 0 eV or more and 0.2 eV or less, preferably 0 eV or more and 0.1 eV or less. Can be mentioned.

  Further, there is no limitation on the light emission colors of the light emitting material included in the light emitting layer 413 and the light emitting material included in the light emitting layer 414, and they may be the same or different. Since the light emission obtained from each is mixed and taken out of the device, the light emitting device can give white light when, for example, the light emission colors of both are complementary colors. In consideration of the reliability of the light-emitting element, the emission peak wavelength of the light-emitting material included in the light-emitting layer 413 is preferably shorter than that of the light-emitting material included in the light-emitting layer 414.

  Note that the light-emitting layer 413 and the light-emitting layer 414 can be formed by an evaporation method (including a vacuum evaporation method), an inkjet method, a coating method, gravure printing, or the like.

  Note that the structure described in this embodiment can be combined as appropriate with any of the structures described in the other embodiments or examples.

(Embodiment 3)
In this embodiment, a display device of one embodiment of the present invention will be described with reference to FIGS.

<Configuration Example 1 of Display Device>
14A is a top view of the display device 600, and FIG. 14B is a cross-sectional view taken along the dashed-dotted line AB and the dashed-dotted line CD in FIG. The display device 600 includes a driver circuit portion (a signal line driver circuit portion 601 and a scan line driver circuit portion 603) and a pixel portion 602. Note that the signal line driver circuit portion 601, the scan line driver circuit portion 603, and the pixel portion 602 have a function of controlling light emission of the light-emitting element.

  In addition, the display device 600 includes an element substrate 610, a sealing substrate 604, a sealant 605, a region 607 surrounded by the sealant 605, a lead wiring 608, and an FPC 609.

  Note that the lead wiring 608 is a wiring for transmitting a signal input to the signal line driver circuit portion 601 and the scanning line driver circuit portion 603, and a video signal, a clock signal, a start signal, an FPC 609 serving as an external input terminal, Receive a reset signal. Note that only the FPC 609 is illustrated here, but a printed wiring board (PWB) may be attached to the FPC 609.

  In the signal line driver circuit portion 601, a CMOS circuit in which an N-channel transistor 623 and a P-channel transistor 624 are combined is formed. Note that the signal line driver circuit portion 601 or the scan line driver circuit portion 603 can use various CMOS circuits, PMOS circuits, or NMOS circuits. In this embodiment mode, a display device in which a driver and a pixel in which a driver circuit portion is formed is provided over the same surface of the substrate is not necessarily required, but the driver circuit portion is not necessarily on the substrate and is externally provided. It can also be formed.

  The pixel portion 602 includes a switching transistor 611, a current control transistor 612, and a lower electrode 613 electrically connected to the drain of the current control transistor 612. A partition wall 614 is formed so as to cover an end portion of the lower electrode 613. As the partition wall 614, a positive photosensitive acrylic resin film can be used.

  In addition, a curved surface having a curvature is formed at the upper end portion or the lower end portion of the partition wall 614 in order to improve the coverage. For example, when positive photosensitive acrylic is used as the material of the partition wall 614, it is preferable that only the upper end portion of the partition wall 614 has a curved surface having a curvature radius (0.2 μm or more and 3 μm or less). As the partition wall 614, either a negative photosensitive resin or a positive photosensitive resin can be used.

  Note that there is no particular limitation on the structure of the transistor (the transistors 611, 612, 623, and 624). For example, a staggered transistor may be used. There is no particular limitation on the polarity of the transistor, and a structure including N-channel and P-channel transistors and a structure including only one of an N-channel transistor and a P-channel transistor may be used. . There is no particular limitation on the crystallinity of a semiconductor film used for the transistor. For example, an amorphous semiconductor film or a crystalline semiconductor film can be used. As the semiconductor material, a group 14 (silicon, etc.) semiconductor, a compound semiconductor (including an oxide semiconductor), an organic semiconductor, or the like can be used. As the transistor, for example, an oxide semiconductor with an energy gap of 2 eV or more, preferably 2.5 eV or more, more preferably 3 eV or more can be used because off-state current of the transistor can be reduced. Examples of the oxide semiconductor include In—Ga oxide and In—M—Zn oxide (M represents Al, Ga, Y, Zr, La, Ce, Sn, Hf, or Nd).

  Note that in the above transistor, an oxide containing the same element is preferably used for the oxide semiconductor layer included in the channel region of the transistor and the oxide layer included in the lower electrode 613. That is, In and a stabilizer M (M represents Al, Si, Ti, Ga, Y, Zr, Sn, La, Ce, Nd, or Hf) in the oxide semiconductor layer used for the channel region of the transistor. It is preferable to have. In addition, it is particularly preferable to use the same material for the oxide semiconductor layer and the oxide layer.

  An EL layer 616 and an upper electrode 617 are formed on the lower electrode 613, respectively. Note that the lower electrode 613 functions as an anode, and the upper electrode 617 functions as a cathode.

  The EL layer 616 is formed by various methods such as an evaporation method using an evaporation mask, an inkjet method, and a spin coating method. Further, as another material forming the EL layer 616, a low molecular compound or a high molecular compound (including an oligomer and a dendrimer) may be used.

  Note that the light-emitting element 618 is formed by the lower electrode 613, the EL layer 616, and the upper electrode 617. A light-emitting element 618 is a light-emitting element having the structure of Embodiment 1. Note that in the case where a plurality of light-emitting elements are formed, the pixel portion may include both the light-emitting elements described in Embodiment 1 and light-emitting elements having other structures.

  Further, the sealing substrate 604 is attached to the element substrate 610 with the sealant 605, whereby the light-emitting element 618 is provided in the region 607 surrounded by the element substrate 610, the sealing substrate 604, and the sealant 605. ing. Note that the region 607 is filled with a filler and is filled with an ultraviolet curable resin or a thermosetting resin that can be used for the sealant 605 in addition to a case where an inert gas (such as nitrogen or argon) is filled. For example, PVC (polyvinyl chloride) resin, acrylic resin, polyimide resin, epoxy resin, silicone resin, PVB (polyvinyl butyral) resin, or EVA (ethylene vinyl acetate) resin may be used. Can be used. When a recess is formed in the sealing substrate and a desiccant is provided therein, deterioration due to the influence of moisture can be suppressed, which is a preferable configuration.

  In addition, the optical element 621 is provided below the sealing substrate 604 so as to overlap with the light emitting element 618. Further, a light shielding layer 622 is provided below the sealing substrate 604. The optical element 621 and the light shielding layer 622 may have structures similar to those of the optical element and the light shielding layer described in Embodiment 1, respectively.

  Note that an epoxy resin or glass frit is preferably used for the sealant 605. Moreover, it is desirable that these materials are materials that are as difficult to permeate moisture and oxygen as possible. In addition to a glass substrate or a quartz substrate, a plastic substrate made of FRP (Fiber Reinforced Plastics), PVF (polyvinyl fluoride), polyester, acrylic, or the like can be used as a material for the sealing substrate 604.

  As described above, a display device including the light-emitting element and the optical element described in Embodiment 1 can be obtained.

<Configuration Example 2 of Display Device>
Next, another example of the display device will be described with reference to FIGS. 15A and 15B and 16 are cross-sectional views of a display device of one embodiment of the present invention.

  FIG. 15A shows a substrate 1001, a base insulating film 1002, a gate insulating film 1003, gate electrodes 1006, 1007, and 1008, a first interlayer insulating film 1020, a second interlayer insulating film 1021, a peripheral portion 1042, and a pixel portion. 1040, a driving circuit portion 1041, light emitting element lower electrodes 1024R, 1024G, and 1024B, a partition wall 1025, an EL layer 1028, a light emitting element upper electrode 1026, a sealing layer 1029, a sealing substrate 1031, a sealing material 1032, and the like are illustrated. Yes.

  15A, a colored layer (a red colored layer 1034R, a green colored layer 1034G, and a blue colored layer 1034B) is provided over a transparent base material 1033 as an example of an optical element. Further, a light shielding layer 1035 may be further provided. The transparent base material 1033 provided with the coloring layer and the light shielding layer is aligned and fixed to the substrate 1001. Note that the coloring layer and the light shielding layer are covered with an overcoat layer 1036. In FIG. 15A, since light transmitted through the colored layer is red, green, and blue, an image can be expressed with pixels of three colors.

  In FIG. 15B, as an example of the optical element, a colored layer (a red colored layer 1034R, a green colored layer 1034G, and a blue colored layer 1034B) is provided between the gate insulating film 1003 and the first interlayer insulating film 1020. An example of forming is shown. As described above, the coloring layer may be provided between the substrate 1001 and the sealing substrate 1031.

  In FIG. 16, as an example of the optical element, a colored layer (a red colored layer 1034R, a green colored layer 1034G, and a blue colored layer 1034B) is provided between the first interlayer insulating film 1020 and the second interlayer insulating film 1021. An example of forming is shown. As described above, the coloring layer may be provided between the substrate 1001 and the sealing substrate 1031.

  In the display device described above, a display device having a structure in which light is extracted to the substrate 1001 side where the transistor is formed (bottom emission type) is used. However, a structure in which light emission is extracted to the sealing substrate 1031 side (top emission type). ) Display device.

<Configuration Example 3 of Display Device>
An example of a cross-sectional view of a top emission type display device is shown in FIGS. 17 and 18 are cross-sectional views illustrating a display device of one embodiment of the present invention, in which the driver circuit portion 1041, the peripheral portion 1042, and the like illustrated in FIGS. 15A and 15B are omitted. doing.

  In this case, a substrate that does not transmit light can be used as the substrate 1001. Until the connection electrode for connecting the transistor and the anode of the light-emitting element is manufactured, the transistor is formed in the same manner as the bottom emission display device. Thereafter, a third interlayer insulating film 1037 is formed so as to cover the electrode 1022. This insulating film may play a role of planarization. The third interlayer insulating film 1037 can be formed using various other materials in addition to the same material as the second interlayer insulating film.

  The lower electrodes 1024R, 1024G, and 1024B of the light-emitting elements are anodes here, but may be cathodes. In the case of a top emission type display device as shown in FIG. 17, it is preferable that the lower electrodes 1024R, 1024G, and 1024B be reflective electrodes. The structures of the lower electrodes 1024R, 1024G, 1024B, and the EL layer 1028 can be similar to the structures of the electrode layer 101, the electrode layer 103, the electrode layer 104, and the EL layer in Embodiment 1, respectively. That is, the lower electrodes 1024R, 1024G, and 1024B preferably include a conductive layer having a function of reflecting light and an oxide layer over the conductive layer. An upper electrode 1026 is provided over the EL layer 1028. By using the upper electrode 1026 as a semi-transmissive / semi-reflective electrode, it is preferable to form a microcavity structure between the lower electrodes 1024R, 1024G, and 1024B and the upper electrode 1026 to increase the light intensity at a specific wavelength.

  In the top emission structure as shown in FIG. 17, sealing can be performed with a sealing substrate 1031 provided with colored layers (a red colored layer 1034R, a green colored layer 1034G, and a blue colored layer 1034B). A light-blocking layer 1035 may be provided on the sealing substrate 1031 so as to be positioned between the pixels. Note that a light-transmitting substrate is preferably used as the sealing substrate 1031.

  FIG. 17 illustrates a plurality of light-emitting elements and a structure in which a colored layer is provided for each of the plurality of light-emitting elements, but is not limited thereto. For example, as shown in FIG. 18, a red colored layer 1034R and a blue colored layer 1034B may be provided without providing a green colored layer, and a full color display may be performed with three colors of red, green, and blue. Good. As shown in FIG. 17, when a light emitting element and a structure in which a colored layer is provided for each of the light emitting elements, an effect of suppressing external light reflection can be obtained. On the other hand, as shown in FIG. 18, when the red colored layer and the blue colored layer are provided without providing the green colored layer, the energy loss of the light emitted from the green light emitting element is small. Therefore, there is an effect that power consumption can be reduced.

  Note that the structure described in this embodiment can be combined as appropriate with any of the other embodiments, the other structures in this embodiment, or the structures described in the examples.

(Embodiment 4)
In this embodiment, a display device including the light-emitting element of one embodiment of the present invention will be described with reference to FIGS.

  FIG. 19A is a block diagram illustrating a display device of one embodiment of the present invention, and FIG. 19B is a circuit diagram illustrating a pixel circuit included in the display device of one embodiment of the present invention. is there.

<Description of display device>
A display device illustrated in FIG. 19A includes a circuit portion (hereinafter referred to as a pixel portion 802) including a pixel of a display element and a circuit for driving the pixel which is provided outside the pixel portion 802. , A driver circuit portion 804), a circuit having an element protection function (hereinafter referred to as a protection circuit 806), and a terminal portion 807. Note that the protection circuit 806 may not be provided.

  Part or all of the driver circuit portion 804 is preferably formed over the same substrate as the pixel portion 802. Thereby, the number of parts and the number of terminals can be reduced. When part or all of the driver circuit portion 804 is not formed over the same substrate as the pixel portion 802, part or all of the driver circuit portion 804 is formed by COG or TAB (Tape Automated Bonding). Can be implemented.

  The pixel portion 802 includes a circuit (hereinafter referred to as a pixel circuit 801) for driving a plurality of display elements arranged in X rows (X is a natural number of 2 or more) and Y columns (Y is a natural number of 2 or more). The driver circuit portion 804 supplies a signal for selecting a pixel (scanning signal) (hereinafter referred to as a scanning line driving circuit 804a) and a signal (data signal) for driving a display element of the pixel. A driver circuit such as a circuit (hereinafter, a signal line driver circuit 804b) is included.

  The scan line driver circuit 804a includes a shift register and the like. The scan line driver circuit 804a receives a signal for driving the shift register via the terminal portion 807 and outputs a signal. For example, the scan line driver circuit 804a receives a start pulse signal, a clock signal, and the like and outputs a pulse signal. The scan line driver circuit 804a has a function of controlling the potential of a wiring to which a scan signal is supplied (hereinafter referred to as scan lines GL_1 to GL_X). Note that a plurality of scan line driver circuits 804a may be provided, and the scan lines GL_1 to GL_X may be divided and controlled by the plurality of scan line driver circuits 804a. Alternatively, the scan line driver circuit 804a has a function of supplying an initialization signal. Note that the present invention is not limited to this, and the scan line driver circuit 804a can supply another signal.

  The signal line driver circuit 804b includes a shift register and the like. In addition to a signal for driving the shift register, the signal line driver circuit 804b receives a signal (image signal) that is a source of a data signal through the terminal portion 807. The signal line driver circuit 804b has a function of generating a data signal to be written in the pixel circuit 801 based on the image signal. In addition, the signal line driver circuit 804b has a function of controlling output of a data signal in accordance with a pulse signal obtained by inputting a start pulse, a clock signal, or the like. The signal line driver circuit 804b has a function of controlling the potential of a wiring to which a data signal is supplied (hereinafter referred to as data lines DL_1 to DL_Y). Alternatively, the signal line driver circuit 804b has a function of supplying an initialization signal. Note that the present invention is not limited to this, and the signal line driver circuit 804b can supply another signal.

  The signal line driver circuit 804b is configured using a plurality of analog switches, for example. The signal line driver circuit 804b can output a signal obtained by time-dividing an image signal as a data signal by sequentially turning on a plurality of analog switches. Alternatively, the signal line driver circuit 804b may be formed using a shift register or the like.

  Each of the plurality of pixel circuits 801 receives a pulse signal through one of the plurality of scanning lines GL to which the scanning signal is applied, and receives the data signal through one of the plurality of data lines DL to which the data signal is applied. Entered. In each of the plurality of pixel circuits 801, writing and holding of data signals is controlled by the scanning line driver circuit 804a. For example, the pixel circuit 801 in the m-th row and the n-th column receives a pulse signal from the scan line driver circuit 804a through the scan line GL_m (m is a natural number equal to or less than X), and the data line DL_n according to the potential of the scan line GL_m. A data signal is input from the signal line driver circuit 804b through (n is a natural number equal to or less than Y).

  The protection circuit 806 illustrated in FIG. 19A is connected to, for example, the scanning line GL that is a wiring between the scanning line driver circuit 804a and the pixel circuit 801. Alternatively, the protection circuit 806 is connected to the data line DL that is a wiring between the signal line driver circuit 804 b and the pixel circuit 801. Alternatively, the protection circuit 806 can be connected to a wiring between the scan line driver circuit 804 a and the terminal portion 807. Alternatively, the protection circuit 806 can be connected to a wiring between the signal line driver circuit 804 b and the terminal portion 807. Note that the terminal portion 807 is a portion where a terminal for inputting a power supply, a control signal, and an image signal from an external circuit to the display device is provided.

  The protection circuit 806 is a circuit that brings a wiring into a conductive state when a potential outside a certain range is applied to the wiring to which the protection circuit 806 is connected.

  As shown in FIG. 19A, by providing a protection circuit 806 in each of the pixel portion 802 and the driver circuit portion 804, resistance of the display device to an overcurrent generated by ESD (Electro Static Discharge) or the like is increased. be able to. However, the structure of the protection circuit 806 is not limited thereto, and for example, a structure in which the protection circuit 806 is connected to the scan line driver circuit 804a or a structure in which the protection circuit 806 is connected to the signal line driver circuit 804b can be employed. Alternatively, the protective circuit 806 can be connected to the terminal portion 807.

  FIG. 19A illustrates an example in which the driver circuit portion 804 is formed using the scan line driver circuit 804a and the signal line driver circuit 804b; however, the present invention is not limited to this structure. For example, a structure in which only the scan line driver circuit 804a is formed and a substrate on which a separately prepared signal line driver circuit is formed (for example, a driver circuit substrate formed of a single crystal semiconductor film or a polycrystalline semiconductor film) is mounted. Also good.

<Configuration example of pixel circuit>
The plurality of pixel circuits 801 illustrated in FIG. 19A can have a structure illustrated in FIG. 19B, for example.

  A pixel circuit 801 illustrated in FIG. 19B includes transistors 852 and 854, a capacitor 862, and a light-emitting element 872.

  One of a source electrode and a drain electrode of the transistor 852 is electrically connected to a wiring (data line DL_n) to which a data signal is supplied. Further, the gate electrode of the transistor 852 is electrically connected to a wiring (scanning line GL_m) to which a gate signal is supplied.

  The transistor 852 has a function of controlling data writing of the data signal.

  One of the pair of electrodes of the capacitor 862 is electrically connected to a wiring to which a potential is applied (hereinafter referred to as a potential supply line VL_a), and the other is electrically connected to the other of the source electrode and the drain electrode of the transistor 852. Is done.

  The capacitor 862 functions as a storage capacitor for storing written data.

  One of a source electrode and a drain electrode of the transistor 854 is electrically connected to the potential supply line VL_a. Further, the gate electrode of the transistor 854 is electrically connected to the other of the source electrode and the drain electrode of the transistor 852.

  One of an anode and a cathode of the light-emitting element 872 is electrically connected to the potential supply line VL_b, and the other is electrically connected to the other of the source electrode and the drain electrode of the transistor 854.

  As the light-emitting element 872, the light-emitting element described in any of Embodiments 1 to 3 can be used.

  Note that one of the potential supply line VL_a and the potential supply line VL_b is supplied with the high power supply potential VDD, and the other is supplied with the low power supply potential VSS.

  In the display device including the pixel circuit 801 in FIG. 19B, for example, the pixel circuit 801 in each row is sequentially selected by the scan line driver circuit 804a illustrated in FIG. Write data.

  The pixel circuit 801 in which data is written is brought into a holding state when the transistor 852 is turned off. Further, the amount of current flowing between the source electrode and the drain electrode of the transistor 854 is controlled in accordance with the potential of the written data signal, and the light-emitting element 872 emits light with luminance corresponding to the flowing current amount. By sequentially performing this for each row, an image can be displayed.

  The light-emitting element of one embodiment of the present invention can be applied to an active matrix method in which an active element is included in a pixel of a display device or a passive matrix method in which an active element is not included in a pixel of a display device. .

  In the active matrix system, not only transistors but also various active elements (active elements and nonlinear elements) can be used as active elements (active elements and nonlinear elements). For example, MIM (Metal Insulator Metal) or TFD (Thin Film Diode) can be used. Since these elements have few manufacturing steps, manufacturing cost can be reduced or yield can be improved. Alternatively, since these elements have small element sizes, the aperture ratio can be improved, and power consumption and luminance can be increased.

  As a method other than the active matrix method, a passive matrix type that does not use an active element (an active element or a non-linear element) can be used. Since no active element (active element or non-linear element) is used, the number of manufacturing steps is small, so that manufacturing costs can be reduced or yield can be improved. Alternatively, since an active element (an active element or a non-linear element) is not used, an aperture ratio can be improved, power consumption can be reduced, or luminance can be increased.

  The structure described in this embodiment can be combined as appropriate with any of the structures described in the other embodiments or examples.

(Embodiment 5)
In this embodiment, a display device including the light-emitting element of one embodiment of the present invention and an electronic device in which the input device is attached to the display device will be described with reference to FIGS.

<Description 1 regarding touch panel>
Note that in this embodiment, a touch panel 2000 including a display device and an input device is described as an example of an electronic device. A case where a touch sensor is used as an example of the input device will be described.

  20A and 20B are perspective views of the touch panel 2000. FIG. 20A and 20B, typical components of the touch panel 2000 are shown for clarity.

  The touch panel 2000 includes a display device 2501 and a touch sensor 2595 (see FIG. 20B). The touch panel 2000 includes a substrate 2510, a substrate 2570, and a substrate 2590. Note that the substrate 2510, the substrate 2570, and the substrate 2590 are all flexible. Note that any one or all of the substrate 2510, the substrate 2570, and the substrate 2590 may not have flexibility.

  The display device 2501 includes a plurality of pixels over the substrate 2510 and a plurality of wirings 2511 that can supply signals to the pixels. The plurality of wirings 2511 are routed to the outer periphery of the substrate 2510, and a part of them constitutes a terminal 2519. A terminal 2519 is electrically connected to the FPC 2509 (1). The plurality of wirings 2511 can supply a signal from the signal line driver circuit 2503s (1) to the plurality of pixels.

  The substrate 2590 includes a touch sensor 2595 and a plurality of wirings 2598 electrically connected to the touch sensor 2595. The plurality of wirings 2598 are drawn around the outer periphery of the substrate 2590, and a part of them constitutes a terminal. The terminal is electrically connected to the FPC 2509 (2). Note that in FIG. 20B, for clarity, electrodes, wirings, and the like of the touch sensor 2595 provided on the back side of the substrate 2590 (the side facing the substrate 2510) are shown by solid lines.

  As the touch sensor 2595, for example, a capacitive touch sensor can be used. Examples of the electrostatic capacity method include a surface electrostatic capacity method and a projection electrostatic capacity method.

  As the projected capacitance method, there are mainly a self-capacitance method and a mutual capacitance method due to a difference in driving method. The mutual capacitance method is preferable because simultaneous multipoint detection is possible.

  Note that a touch sensor 2595 illustrated in FIG. 20B has a structure to which a projected capacitive touch sensor is applied.

  Note that as the touch sensor 2595, various sensors that can detect the proximity or contact of a detection target such as a finger can be used.

  The projected capacitive touch sensor 2595 includes an electrode 2591 and an electrode 2592. The electrode 2591 is electrically connected to any of the plurality of wirings 2598, and the electrode 2592 is electrically connected to any other of the plurality of wirings 2598.

  As shown in FIGS. 20A and 20B, the electrode 2592 has a shape in which a plurality of quadrilaterals repeatedly arranged in one direction are connected at corners.

  The electrode 2591 has a quadrangular shape and is repeatedly arranged in a direction intersecting with the direction in which the electrode 2592 extends.

  The wiring 2594 is electrically connected to two electrodes 2591 that sandwich the electrode 2592. At this time, a shape in which the area of the intersection of the electrode 2592 and the wiring 2594 is as small as possible is preferable. Thereby, the area of the area | region in which the electrode is not provided can be reduced, and the dispersion | variation in the transmittance | permeability can be reduced. As a result, variation in luminance of light transmitted through the touch sensor 2595 can be reduced.

  Note that the shapes of the electrode 2591 and the electrode 2592 are not limited thereto, and various shapes can be employed. For example, a plurality of electrodes 2591 may be arranged so as not to have a gap as much as possible, and a plurality of electrodes 2592 may be provided apart from each other so as to form a region that does not overlap with the electrodes 2591 with an insulating layer interposed therebetween. At this time, it is preferable to provide a dummy electrode electrically insulated from two adjacent electrodes 2592 because the area of regions having different transmittances can be reduced.

<Description of display device>
Next, details of the display device 2501 will be described with reference to FIG. FIG. 21A corresponds to a cross-sectional view taken along dashed-dotted line X1-X2 in FIG.

  The display device 2501 includes a plurality of pixels arranged in a matrix. The pixel includes a display element and a pixel circuit that drives the display element.

  In the following description, a case where a light-emitting element that emits white light is applied to a display element will be described; however, the display element is not limited to this. For example, light emitting elements having different emission colors may be applied so that the color of light emitted from each adjacent pixel is different.

For example, the substrate 2510 and the substrate 2570 have a water vapor transmission rate of 1 × 10 ⁻⁵ g · m ⁻² · day ⁻¹ or less, preferably 1 × 10 ⁻⁶ g · m ⁻² · day ⁻¹ or less. A flexible material can be preferably used. Alternatively, it is preferable to use a material in which the thermal expansion coefficient of the substrate 2510 and the thermal expansion coefficient of the substrate 2570 are approximately equal. For example, a material having a linear expansion coefficient of 1 × 10 ⁻³ / K or less, preferably 5 × 10 ⁻⁵ / K or less, more preferably 1 × 10 ⁻⁵ / K or less can be suitably used.

  Note that the substrate 2510 is a stack including an insulating layer 2510a that prevents diffusion of impurities into the light-emitting element, a flexible substrate 2510b, and an adhesive layer 2510c that bonds the insulating layer 2510a and the flexible substrate 2510b. . The substrate 2570 is a stack including an insulating layer 2570a that prevents diffusion of impurities into the light-emitting element, a flexible substrate 2570b, and an adhesive layer 2570c that bonds the insulating layer 2570a and the flexible substrate 2570b. .

  As the adhesive layer 2510c and the adhesive layer 2570c, for example, a material containing polyester, polyolefin, polyamide (nylon, aramid, or the like), polyimide, polycarbonate, polyurethane, acrylic resin, epoxy resin, or a resin having a siloxane bond can be used.

  In addition, a sealing layer 2560 is provided between the substrate 2510 and the substrate 2570. The sealing layer 2560 preferably has a refractive index larger than that of air. In addition, as illustrated in FIG. 21A, in the case where light is extracted to the sealing layer 2560 side, the sealing layer 2560 can also serve as an optical bonding layer.

  Further, a sealing material may be formed on the outer peripheral portion of the sealing layer 2560. By using the sealant, the light-emitting element 2550R can be provided in the region surrounded by the substrate 2510, the substrate 2570, the sealing layer 2560, and the sealant. Note that the sealing layer 2560 may be filled with an inert gas (such as nitrogen or argon). In addition, a drying material may be provided in the inert gas to adsorb moisture or the like. Moreover, as the above-mentioned sealing material, for example, it is preferable to use an epoxy resin or glass frit. As a material used for the sealant, a material that does not transmit moisture and oxygen is preferably used.

  In addition, the display device 2501 includes a pixel 2502R. In addition, the pixel 2502R includes a light emitting module 2580R.

  The pixel 2502R includes a light-emitting element 2550R and a transistor 2502t that can supply power to the light-emitting element 2550R. Note that the transistor 2502t functions as part of the pixel circuit. The light emitting module 2580R includes a light emitting element 2550R and a colored layer 2567R.

  The light-emitting element 2550R includes a lower electrode, an upper electrode, and an EL layer between the lower electrode and the upper electrode. As the light-emitting element 2550R, for example, the light-emitting element described in any of Embodiments 1 to 3 can be used.

  Moreover, a microcavity structure may be formed between the lower electrode and the upper electrode to increase the light intensity at a specific wavelength.

  In the case where the sealing layer 2560 is provided on the light extraction side, the sealing layer 2560 is in contact with the light-emitting element 2550R and the coloring layer 2567R.

  The coloring layer 2567R is in a position overlapping with the light-emitting element 2550R. Thus, part of the light emitted from the light emitting element 2550R passes through the colored layer 2567R and is emitted to the outside of the light emitting module 2580R in the direction of the arrow shown in the drawing.

  The display device 2501 is provided with a light-blocking layer 2567BM in the direction of emitting light. The light-blocking layer 2567BM is provided so as to surround the colored layer 2567R.

  The coloring layer 2567R may have a function of transmitting light in a specific wavelength band, for example, a color filter that transmits light in a red wavelength band, a color filter that transmits light in a green wavelength band, A color filter that transmits light in the blue wavelength band, a color filter that transmits light in the yellow wavelength band, and the like can be used. Each color filter can be formed using a variety of materials by a printing method, an inkjet method, an etching method using a photolithography technique, or the like.

  In addition, the display device 2501 is provided with an insulating layer 2521. The insulating layer 2521 covers the transistor 2502t. Note that the insulating layer 2521 has a function of planarizing unevenness caused by the pixel circuit. Further, the insulating layer 2521 may have a function of suppressing impurity diffusion. Accordingly, a decrease in reliability of the transistor 2502t and the like due to impurity diffusion can be suppressed.

  The light-emitting element 2550R is formed above the insulating layer 2521. In addition, the lower electrode included in the light-emitting element 2550R is provided with a partition wall 2528 which overlaps with an end portion of the lower electrode. Note that a spacer for controlling the distance between the substrate 2510 and the substrate 2570 may be formed over the partition wall 2528.

  The scan line driver circuit 2503g (1) includes a transistor 2503t and a capacitor 2503c. Note that the driver circuit can be formed over the same substrate in the same process as the pixel circuit.

  A wiring 2511 capable of supplying a signal is provided over the substrate 2510. A terminal 2519 is provided over the wiring 2511. In addition, the FPC 2509 (1) is electrically connected to the terminal 2519. The FPC 2509 (1) has a function of supplying a video signal, a clock signal, a start signal, a reset signal, and the like. Note that a printed wiring board (PWB) may be attached to the FPC 2509 (1).

  Further, transistors with various structures can be used for the display device 2501. FIG. 21A illustrates the case where a bottom-gate transistor is used; however, the invention is not limited to this. For example, a top-gate transistor illustrated in FIG. It is good also as a structure applied to.

  There is no particular limitation on the polarity of the transistor 2502t and the transistor 2503t, and a structure including an N-channel transistor and a P-channel transistor, or a structure including only one of an N-channel transistor and a P-channel transistor is used. It may be used. Further, there is no particular limitation on the crystallinity of the semiconductor film used for the transistors 2502t and 2503t. For example, an amorphous semiconductor film or a crystalline semiconductor film can be used. As the semiconductor material, a Group 13 semiconductor (eg, a semiconductor containing gallium), a Group 14 semiconductor (eg, a semiconductor containing silicon), a compound semiconductor (including an oxide semiconductor), an organic semiconductor, or the like is used. it can. By using an oxide semiconductor with an energy gap of 2 eV or more, preferably 2.5 eV or more, more preferably 3 eV or more for either or both of the transistor 2502t and the transistor 2503t, the off-state current of the transistor can be reduced. Therefore, it is preferable. Examples of the oxide semiconductor include In—Ga oxide and In—M—Zn oxide (M represents Al, Ga, Y, Zr, La, Ce, Sn, Hf, or Nd).

<Explanation about touch sensor>
Next, details of the touch sensor 2595 will be described with reference to FIG. FIG. 21C corresponds to a cross-sectional view taken along dashed-dotted line X3-X4 in FIG.

  The touch sensor 2595 includes electrodes 2591 and electrodes 2592 that are arranged in a staggered pattern on the substrate 2590, an insulating layer 2593 that covers the electrodes 2591 and 2592, and wiring 2594 that electrically connects adjacent electrodes 2591.

  The electrodes 2591 and 2592 are formed using a light-transmitting conductive material. As the light-transmitting conductive material, a conductive oxide such as indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, or zinc oxide to which gallium is added can be used. Note that a film containing graphene can also be used. The film containing graphene can be formed, for example, by reducing a film containing graphene oxide formed in a film shape. Examples of the reduction method include a method of applying heat.

  For example, after forming a light-transmitting conductive material over the substrate 2590 by a sputtering method, unnecessary portions are removed by various pattern formation techniques such as a photolithography method, so that the electrode 2591 and the electrode 2592 are formed. can do.

  As a material used for the insulating layer 2593, for example, an inorganic insulating material such as silicon oxide, silicon oxynitride, or aluminum oxide can be used in addition to a resin such as acrylic or epoxy, or a resin having a siloxane bond.

  An opening reaching the electrode 2591 is provided in the insulating layer 2593 so that the wiring 2594 is electrically connected to the adjacent electrode 2591. Since the light-transmitting conductive material can increase the aperture ratio of the touch panel, it can be preferably used for the wiring 2594. A material having higher conductivity than the electrodes 2591 and 2592 can be preferably used for the wiring 2594 because electric resistance can be reduced.

  The electrode 2592 extends in one direction, and a plurality of electrodes 2592 are provided in a stripe shape. The wiring 2594 is provided so as to intersect with the electrode 2592.

  A pair of electrodes 2591 is provided with one electrode 2592 interposed therebetween. The wiring 2594 electrically connects the pair of electrodes 2591.

  Note that the plurality of electrodes 2591 are not necessarily arranged in a direction orthogonal to the one electrode 2592, and may be arranged to form an angle of more than 0 degree and less than 90 degrees.

  The wiring 2598 is electrically connected to the electrode 2591 or the electrode 2592. In addition, part of the wiring 2598 functions as a terminal. As the wiring 2598, for example, a metal material such as aluminum, gold, platinum, silver, nickel, titanium, tungsten, chromium, molybdenum, iron, cobalt, copper, or palladium, or an alloy material containing the metal material is used. it can.

  Note that an insulating layer that covers the insulating layer 2593 and the wiring 2594 may be provided to protect the touch sensor 2595.

  The connection layer 2599 electrically connects the wiring 2598 and the FPC 2509 (2).

  As the connection layer 2599, an anisotropic conductive film (ACF: Anisotropic Conductive Film), an anisotropic conductive paste (ACP: Anisotropic Conductive Paste), or the like can be used.

<Description 2 regarding touch panel>
Next, details of the touch panel 2000 will be described with reference to FIG. FIG. 22A corresponds to a cross-sectional view taken along dashed-dotted line X5-X6 in FIG.

  A touch panel 2000 illustrated in FIG. 22A has a structure in which the display device 2501 described in FIG. 21A and the touch sensor 2595 described in FIG.

  In addition to the structure described in FIGS. 21A and 21C, the touch panel 2000 illustrated in FIG. 22A includes an adhesive layer 2597 and an antireflection layer 2567p.

  The adhesive layer 2597 is provided in contact with the wiring 2594. Note that the adhesive layer 2597 attaches the substrate 2590 to the substrate 2570 so that the touch sensor 2595 overlaps the display device 2501. The adhesive layer 2597 preferably has a light-transmitting property. For the adhesive layer 2597, a thermosetting resin or an ultraviolet curable resin can be used. For example, an acrylic resin, a urethane resin, an epoxy resin, or a siloxane resin can be used.

  The antireflection layer 2567p is provided at a position overlapping the pixel. As the antireflection layer 2567p, for example, a circularly polarizing plate can be used.

  Next, a touch panel having a structure different from that illustrated in FIG. 22A will be described with reference to FIG.

  FIG. 22B is a cross-sectional view of the touch panel 2001. A touch panel 2001 illustrated in FIG. 22B is different from the touch panel 2000 illustrated in FIG. 22A in the position of the touch sensor 2595 with respect to the display device 2501. Here, different configurations will be described in detail, and the description of the touch panel 2000 is used for a portion where a similar configuration can be used.

  The coloring layer 2567R is in a position overlapping with the light-emitting element 2550R. In addition, the light-emitting element 2550R illustrated in FIG. 22B emits light to the side where the transistor 2502t is provided. Thus, part of the light emitted from the light emitting element 2550R passes through the colored layer 2567R and is emitted to the outside of the light emitting module 2580R in the direction of the arrow shown in the drawing.

  The touch sensor 2595 is provided on the substrate 2510 side of the display device 2501.

  An adhesive layer 2597 is provided between the substrate 2510 and the substrate 2590, and the display device 2501 and the touch sensor 2595 are attached to each other.

  As shown in FIGS. 22A and 22B, light emitted from the light emitting element may be emitted to one or both of the upper surface and the lower surface of the substrate.

<Explanation regarding touch panel drive method>
Next, an example of a touch panel driving method will be described with reference to FIGS.

  FIG. 23A is a block diagram illustrating a structure of a mutual capacitive touch sensor. FIG. 23A illustrates a pulse voltage output circuit 2601 and a current detection circuit 2602. Note that in FIG. 23A, the electrode 2621 to which a pulse voltage is applied is represented by X1-X6, and the electrode 2622 for detecting a change in current is represented by Y1-Y6. FIG. 23A illustrates a capacitor 2603 formed by the overlap of the electrode 2621 and the electrode 2622. Note that the functions of the electrode 2621 and the electrode 2622 may be interchanged.

  The pulse voltage output circuit 2601 is a circuit for sequentially applying pulses to the wiring lines X1 to X6. When a pulse voltage is applied to the wiring of X1-X6, an electric field is generated between the electrode 2621 and the electrode 2622 forming the capacitor 2603. By utilizing the fact that the electric field generated between the electrodes causes a change in the mutual capacitance of the capacitor 2603 due to shielding or the like, it is possible to detect the proximity or contact of the detection object.

  The current detection circuit 2602 is a circuit for detecting a change in current in the wiring of Y1-Y6 due to a change in mutual capacitance in the capacitor 2603. In the wiring of Y1-Y6, there is no change in the current value detected when there is no proximity or contact with the detected object, but the current value when the mutual capacitance decreases due to the proximity or contact with the detected object. Detect changes that decrease. Note that current detection may be performed using an integration circuit or the like.

  Next, FIG. 23B shows a timing chart of input / output waveforms in the mutual capacitance type touch sensor shown in FIG. In FIG. 23B, it is assumed that the detection target is detected in each matrix in one frame period. FIG. 23B shows two cases, that is, a case where the detected object is not detected (non-touch) and a case where the detected object is detected (touch). In addition, about the wiring of Y1-Y6, the waveform made into the voltage value corresponding to the detected electric current value is shown.

  A pulse voltage is sequentially applied to the X1-X6 wiring, and the waveform of the Y1-Y6 wiring changes according to the pulse voltage. When there is no proximity or contact of the detection object, the waveform of Y1-Y6 changes uniformly according to the change of the voltage of the wiring of X1-X6. On the other hand, since the current value decreases at the location where the detection object is close or in contact, the waveform of the voltage value corresponding to this also changes.

  In this way, by detecting the change in mutual capacitance, the proximity or contact of the detection target can be detected.

<Explanation about sensor circuit>
FIG. 23A illustrates a passive matrix touch sensor in which only a capacitor 2603 is provided at a wiring intersection as a touch sensor; however, an active matrix touch sensor including a transistor and a capacitor may be used. An example of a sensor circuit included in the active matrix touch sensor is shown in FIG.

  The sensor circuit illustrated in FIG. 24 includes a capacitor 2603, a transistor 2611, a transistor 2612, and a transistor 2613.

  The gate of the transistor 2613 is supplied with the signal G2, the voltage VRES is supplied to one of a source and a drain, and the other is electrically connected to one electrode of the capacitor 2603 and the gate of the transistor 2611. In the transistor 2611, one of a source and a drain is electrically connected to one of a source and a drain of the transistor 2612, and the voltage VSS is supplied to the other. In the transistor 2612, the gate is supplied with the signal G1, and the other of the source and the drain is electrically connected to the wiring ML. The voltage VSS is applied to the other electrode of the capacitor 2603.

  Next, the operation of the sensor circuit shown in FIG. 24 will be described. First, a potential for turning on the transistor 2613 is supplied as the signal G2, so that a potential corresponding to the voltage VRES is applied to the node n to which the gate of the transistor 2611 is connected. Next, a potential for turning off the transistor 2613 is supplied as the signal G2, so that the potential of the node n is held.

  Subsequently, the potential of the node n changes from VRES as the mutual capacitance of the capacitor 2603 changes due to the proximity or contact of a detection object such as a finger.

  In the reading operation, a potential for turning on the transistor 2612 is supplied to the signal G1. The current flowing through the transistor 2611, that is, the current flowing through the wiring ML is changed in accordance with the potential of the node n. By detecting this current, the proximity or contact of the detection object can be detected.

  As the transistor 2611, the transistor 2612, and the transistor 2613, an oxide semiconductor layer is preferably used for a semiconductor layer in which a channel region is formed. In particular, when such a transistor is used as the transistor 2613, the potential of the node n can be held for a long time, and the frequency of the operation of supplying VRES to the node n (refresh operation) can be reduced. it can.

  The structure described in this embodiment can be combined as appropriate with any of the structures described in the other embodiments or examples.

(Embodiment 6)
In this embodiment, a display module and an electronic device each including the light-emitting element of one embodiment of the present invention will be described with reference to FIGS.

<Explanation about display module>
A display module 8000 illustrated in FIG. 25 includes a touch sensor 8004 connected to the FPC 8003, a display device 8006 connected to the FPC 8005, a frame 8009, a printed circuit board 8010, and a battery 8011 between an upper cover 8001 and a lower cover 8002. .

  The light-emitting element of one embodiment of the present invention can be used for the display device 8006, for example.

  The shapes and dimensions of the upper cover 8001 and the lower cover 8002 can be changed as appropriate in accordance with the sizes of the touch sensor 8004 and the display device 8006.

  As the touch sensor 8004, a resistive touch sensor or a capacitive touch sensor can be used by being superimposed on the display device 8006. In addition, the counter substrate (sealing substrate) of the display device 8006 can have a touch sensor function. In addition, an optical sensor may be provided in each pixel of the display device 8006 to provide an optical touch sensor.

  The frame 8009 has a function as an electromagnetic shield for blocking electromagnetic waves generated by the operation of the printed board 8010 in addition to a protective function of the display device 8006. The frame 8009 may have a function as a heat sink.

  The printed board 8010 includes a power supply circuit, a signal processing circuit for outputting a video signal and a clock signal. As a power supply for supplying power to the power supply circuit, an external commercial power supply may be used, or a power supply using a battery 8011 provided separately may be used. The battery 8011 can be omitted when a commercial power source is used.

  The display module 8000 may be additionally provided with a member such as a polarizing plate, a retardation plate, or a prism sheet.

<Explanation about electronic equipment>
FIGS. 26A to 26G illustrate electronic devices. These electronic devices include a housing 9000, a display portion 9001, a speaker 9003, operation keys 9005 (including a power switch or operation switch), a connection terminal 9006, and a sensor 9007 (force, displacement, position, speed, acceleration, angular velocity, Includes functions to measure rotation speed, distance, light, liquid, magnetism, temperature, chemical, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor or infrared ), A microphone 9008, and the like.

  The electronic devices illustrated in FIGS. 26A to 26G can have a variety of functions. For example, a function for displaying various information (still images, moving images, text images, etc.) on the display unit, a touch sensor function, a function for displaying a calendar, date or time, etc., a function for controlling processing by various software (programs) , Wireless communication function, function to connect to various computer networks using wireless communication function, function to transmit or receive various data using wireless communication function, read program or data recorded in recording medium A function of displaying on the display portion can be provided. Note that the functions of the electronic devices illustrated in FIGS. 26A to 26G are not limited to these, and can have various functions. Although not illustrated in FIGS. 26A to 26G, the electronic device may have a plurality of display portions. In addition, the electronic device is equipped with a camera, etc., to capture still images, to capture moving images, to store captured images on a recording medium (externally or built into the camera), and to display captured images on the display unit And the like.

  Details of the electronic devices illustrated in FIGS. 26A to 26G are described below.

  FIG. 26A is a perspective view showing a portable information terminal 9100. A display portion 9001 included in the portable information terminal 9100 has flexibility. Therefore, the display portion 9001 can be incorporated along the curved surface of the curved housing 9000. Further, the display portion 9001 includes a touch sensor and can be operated by touching the screen with a finger, a stylus, or the like. For example, an application can be activated by touching an icon displayed on the display unit 9001.

  FIG. 26B is a perspective view showing the portable information terminal 9101. The portable information terminal 9101 has one or a plurality of functions selected from, for example, a telephone, a notebook, an information browsing device, or the like. Specifically, it can be used as a smartphone. Note that the portable information terminal 9101 is illustrated with the speaker 9003, the connection terminal 9006, the sensor 9007, and the like omitted, but can be provided at the same position as the portable information terminal 9100 illustrated in FIG. Further, the portable information terminal 9101 can display characters and image information on the plurality of surfaces. For example, three operation buttons 9050 (also referred to as operation icons or simply icons) can be displayed on one surface of the display portion 9001. Further, information 9051 indicated by a broken-line rectangle can be displayed on another surface of the display portion 9001. As an example of the information 9051, a display for notifying an incoming call such as an e-mail, SNS (social networking service), a telephone call, a title such as an e-mail or SNS, a sender name such as an e-mail or SNS, a date and time, and a time , Battery level, antenna reception strength and so on. Alternatively, an operation button 9050 or the like may be displayed instead of the information 9051 at a position where the information 9051 is displayed.

  FIG. 26C is a perspective view showing the portable information terminal 9102. The portable information terminal 9102 has a function of displaying information on three or more surfaces of the display portion 9001. Here, an example is shown in which information 9052, information 9053, and information 9054 are displayed on different planes. For example, the user of the portable information terminal 9102 can check the display (information 9053 here) in a state where the portable information terminal 9102 is stored in the chest pocket of clothes. Specifically, the telephone number or name of the caller of the incoming call is displayed at a position where it can be observed from above portable information terminal 9102. The user can check the display and determine whether to receive a call without taking out the portable information terminal 9102 from the pocket.

  FIG. 26D is a perspective view showing a wristwatch-type portable information terminal 9200. The portable information terminal 9200 can execute various applications such as a mobile phone, electronic mail, text browsing and creation, music playback, Internet communication, and computer games. Further, the display portion 9001 is provided with a curved display surface, and can perform display along the curved display surface. In addition, the portable information terminal 9200 can execute short-range wireless communication with a communication standard. For example, it is possible to talk hands-free by communicating with a headset capable of wireless communication. In addition, the portable information terminal 9200 includes a connection terminal 9006 and can directly exchange data with other information terminals via a connector. Charging can also be performed through the connection terminal 9006. Note that the charging operation may be performed by wireless power feeding without using the connection terminal 9006.

  26E, 26F, and 26G are perspective views illustrating a foldable portable information terminal 9201. FIG. FIG. 26E is a perspective view of a state in which the portable information terminal 9201 is expanded, and FIG. 26F is a state in which the portable information terminal 9201 is expanded or is in the middle of changing from the folded state to the other. FIG. 26G is a perspective view of the portable information terminal 9201 folded. The portable information terminal 9201 is excellent in portability in the folded state, and in the expanded state, the portable information terminal 9201 is excellent in display listability due to a seamless wide display area. A display portion 9001 included in the portable information terminal 9201 is supported by three housings 9000 connected by a hinge 9055. By bending between the two housings 9000 via the hinge 9055, the portable information terminal 9201 can be reversibly deformed from the expanded state to the folded state. For example, the portable information terminal 9201 can be bent with a curvature radius of 1 mm to 150 mm.

  The electronic device described in this embodiment includes a display portion for displaying some information. Note that the light-emitting element of one embodiment of the present invention can also be applied to an electronic device having no display portion. In addition, in the display portion of the electronic device described in this embodiment, an example of a configuration that has flexibility and can display along a curved display surface, or a configuration of a foldable display portion is given. However, the present invention is not limited to this, and may have a configuration in which display is performed on a flat portion without having flexibility.

  The structure described in this embodiment can be combined as appropriate with any of the structures described in the other embodiments or examples.

(Embodiment 7)
In this embodiment, an example of a lighting device to which the light-emitting element which is one embodiment of the present invention is applied will be described with reference to FIGS.

  FIG. 27 illustrates an example in which the light-emitting element is used as an indoor lighting device 8501. Note that since the light-emitting element can have a large area, a large-area lighting device can be formed. In addition, by using a housing having a curved surface, the lighting device 8502 in which the light-emitting region has a curved surface can be formed. The light-emitting element described in this embodiment is thin and has a high degree of freedom in housing design. Therefore, it is possible to form a lighting device with various designs. Further, a large lighting device 8503 may be provided on the indoor wall surface. Alternatively, the lighting devices 8501, 8502, and 8503 may be provided with touch sensors to turn the power on or off.

  In addition, by using the light-emitting element on the surface side of the table, the lighting device 8504 having a function as a table can be obtained. Note that a lighting device having a function as furniture can be obtained by using a light-emitting element as part of other furniture.

  As described above, various lighting devices to which the light-emitting element is applied can be obtained. Note that these lighting devices are included in one embodiment of the present invention.

  The structure described in this embodiment can be combined as appropriate with any of the structures described in the other embodiments or examples.

  In this example, an example of manufacturing an electrode layer (electrode 1 and electrode 2) which is one embodiment of the present invention and a comparative electrode layer (comparative electrode 1) is shown. Note that as reference numerals and the like used in this example, the light-emitting element 290 illustrated in FIG. 7A of Embodiment 1 is used as an example.

<1-1. Production of electrode 1>
An Al—Ni—La film was formed to a thickness of 200 nm on the substrate 200 as the conductive layer 101a constituting the electrode layer. Next, an In—Ga—Zn oxide was formed to a thickness of 10 nm as the oxide layer 101b in contact with the conductive layer 101a. At this time, the atomic ratio of the metal element of the sputtering target was In: Ga: Zn = 1: 1: 1, and the substrate temperature was 300 ° C. After that, an ITSO film having a thickness of 10 nm was formed as the transparent conductive film 101c over the oxide layer 101b. After the ITSO film was formed, baking was performed at 250 ° C. and 300 ° C. for 1 hour, respectively. The electrode 1 was produced through the above steps.

<1-2. Production of electrode 2>
The electrode 2 is different in the process of forming the oxide layer 101b of the electrode 1 described above, and the other processes are the same manufacturing methods as those of the electrode 1. That is, when an In—Ga—Zn oxide film is formed as the oxide layer 101b, the atomic ratio of the metal elements of the sputtering target is In: Ga: Zn = 1: 3: 6, and the substrate temperature is 300. The film was formed at 0 ° C.

<1-3. Preparation of Comparative Electrode 1>
The comparative electrode 1 is different in the process of forming the oxide layer 101b of the electrode 1 described above, and the other processes are the same manufacturing methods as those of the electrode 1. That is, instead of the oxide layer 101b, a Ti film was formed to a thickness of 6 nm and then baked at 300 ° C. for 1 hour to oxidize the Ti film and form a titanium oxide film.

<1-4. Electrode characteristics>
The reflectances of the electrode 1, the electrode 2, and the comparative electrode 1 are shown in FIG.

  The reflectivity of the electrode 1 and the electrode 2 is higher than the reflectivity of the comparative electrode 1 and shows an excellent reflectivity. Thus, an electrode having excellent reflectance can be formed by using one embodiment of the present invention for the electrode layer.

  Electrode 1 and electrode 2 did not cause electrolytic corrosion and did not peel off. Therefore, it was found that this is a stable electrode layer suitable for use as an electrode layer of a light emitting element.

Note that the resistivity of the In—Ga—Zn oxide (1: 1: 1) used as the oxide layer 101b was measured and found to be 5.5 × 10 ⁻³ Ωm. This is about the same as the resistivity of ITSO used as a transparent conductive film of 2.6 × 10 ⁻³ Ωm, and is sufficiently low to be used as an electrode of a light emitting element.

  Therefore, an electrode using the oxide layer of one embodiment of the present invention has high reflectance and low resistivity, and thus can be said to be suitable as an electrode of a light-emitting element.

  As described above, the structure described in this example can be combined with any of the other examples and embodiments as appropriate.

  In this example, manufacturing examples of light-emitting elements (light-emitting element 1 and light-emitting element 2) which are one embodiment of the present invention will be described. FIG. 29A shows a schematic cross-sectional view of a light-emitting element manufactured in this example, and Table 4 shows details of the element structure. The structures and abbreviations of the compounds used are shown below.

<2-1. Production of Light-Emitting Element 1>
An Al—Ni—La film was formed to a thickness of 200 nm as the conductive layer 501a included in the electrode layer 501 over the substrate 510.

  Next, an In—Ga—Zn oxide was formed to a thickness of 10 nm as the oxide layer 501b in contact with the conductive layer 501a. At this time, the atomic ratio of the metal element of the sputtering target was In: Ga: Zn = 1: 1: 1, and the substrate temperature was 300 ° C.

Next, an ITSO film having a thickness of 40 nm was formed as a transparent conductive film 501c over the oxide layer 501b. The electrode layer 501 was formed by the above process. The electrode area of the electrode layer 501 was 4 mm ² (2 mm × 2 mm).

Next, 3- [4- (9-phenanthryl) -phenyl] -9-phenyl-9H-carbazole (abbreviation: PCPPn), molybdenum oxide (MoO ₃ ), and the hole injection layer 531 are formed over the electrode layer 501. Was co-evaporated so that the weight ratio (PCPPn: MoO ₃ ) was 1: 0.5 and the thickness was 13.5 nm.

  Next, PCPPn was deposited as a hole transport layer 532 on the hole injection layer 531 so as to have a thickness of 10 nm.

  Next, as the light-emitting layer 521 over the hole-transport layer 532, 9- [4- (10-phenyl-9-anthracenyl) phenyl] -9H-carbazole (abbreviation: CzPA) and N, N′-bis (3 -Methylphenyl) -N, N′-bis [3- (9-phenyl-9H-fluoren-9-yl) phenyl] pyrene-1,6-diamine (abbreviation: 1,6 mM emFLPAPrn) and a weight ratio (CzPA: (1,6mMemFLPAPrn) was 1: 0.05 and the thickness was 25 nm. In the light emitting layer 521, CzPA is a host material, and 1,6 mM emFLPAPrn is a guest material (fluorescent material).

  Next, CzPA and bathophenanthroline (abbreviation: Bphen) were sequentially deposited as an electron transport layer 533 on the light-emitting layer 521 so that the thicknesses were 5 nm and 15 nm, respectively.

Next, Li ₂ O and copper phthalocyanine (abbreviation: CuPc) were deposited as the electron injecting layer 534 to have a thickness of 0.1 nm and 2 nm, respectively.

Next, as a charge generation layer 535 that also serves as a hole injection layer, 4,4 ′, 4 ″-(benzene-1,3,5-triyl) tri (dibenzothiophene) (abbreviation: DBT3P-II), MoO ₃ was co-deposited so that the weight ratio (DBT3P-II: MoO ₃ ) was 1: 0.5 and the thickness was 12.5 nm.

  Next, 4-phenyl-4 ′-(9-phenylfluoren-9-yl) triphenylamine (abbreviation: BPAFLP) is formed as a hole transporting layer 537 over the charge generation layer 535 so as to have a thickness of 20 nm. Vapor deposited.

Next, as the light-emitting layer 522 over the hole-transport layer 537, 2- [3 ′-(dibenzothiophen-4-yl) biphenyl-3-yl] dibenzo [f, h] quinoxaline (abbreviation: 2mDBTBPDBq-II) and 4,4′-di (1-naphthyl) -4 ″-(9-phenyl-9H-carbazol-3-yl) triphenylamine (abbreviation: PCBNBB) and (acetylacetonato) bis (6-tert -Butyl-4-phenylpyrimidinato) iridium (III) (abbreviation: Ir (tBupppm) ₂ (acac)) and a weight ratio (2mDBTBPDBq-II: PCNBBB: Ir (tBupppm) ₂ (acac)) of 0. 7: 0.3: 0.06 and co-evaporated to a thickness of 20 nm. Further, 2mDBTBPDBq-II and bis {4,6-dimethyl-2- [3- (3,5-dimethylphenyl) -5-phenyl-2-pyrazinyl-κN] phenyl-κC} (2,6-dimethyl- 3,5-heptanedionato-κ ² O, O ′) iridium (III) (abbreviation: Ir (dmdppr-P) ₂ (divm)) and weight ratio (2mDBTBPDBq-II: Ir (dmdppr-P) ₂ (divm )) Was 1: 0.04 and the thickness was 20 nm. Note that in the light-emitting layer 522, 2mDBTBPDBq-II is a host material, PCBNBB is an assist material, and Ir (tBupppm) ₂ (acac) and Ir (dmdppr-P) ₂ (divm) are guest materials (phosphorescent materials).

  Next, 2mDBTPBPDBq-II and Bphen are sequentially deposited on the light-emitting layer 522 as an electron transport layer 538 so that the thicknesses become 30 nm and 15 nm, respectively, and as an electron injection layer 539 on the electron transport layer 538, a fluorine is formed. Lithium fluoride (LiF) was deposited to 1 nm.

  Next, a silver (Ag) and magnesium (Mg) alloy film and an ITO film were formed as an electrode layer 502 on the electron injection layer 539 so as to have thicknesses of 15 nm and 70 nm, respectively. Note that the alloy film of Ag and Mg was deposited so that the volume ratio (Ag: Mg) was 1: 0.1.

  Through the above steps, a structure formed over the substrate 510 was manufactured. Note that, in the above-described film formation process, evaporation was all performed by a resistance heating method. The ITO film of the electrode layer 502 was formed by a sputtering method.

  In addition, a green color filter was formed as the optical element 514 on the sealing substrate 512 of the light emitting element 1.

Next, the light emitting element 1 was sealed by fixing the sealing substrate 512 on the substrate 510 using an organic EL sealing material in a glove box in a nitrogen atmosphere. Specifically, a sealing material is applied to the periphery of the light emitting element, the substrate 510 and the sealing substrate 512 are bonded together, ultraviolet light having a wavelength of 365 nm is irradiated with 6 J / cm ² , and heat treatment is performed at 80 ° C. for 1 hour. did. The light emitting element 1 was obtained through the above steps.

<2-2. Production of Light-Emitting Element 2>
The light-emitting element 2 differs from the light-emitting element 1 described above only in the following steps, and the other steps are the same as those for the light-emitting element 1.

  As the oxide layer 501b in contact with the conductive layer 501a included in the electrode layer 501, an In—Ga—Zn oxide was formed to a thickness of 10 nm. At this time, the atomic ratio of the metal element of the sputtering target was In: Ga: Zn = 1: 3: 6, and the substrate temperature was 300 ° C.

Further, as a hole injection layer 531 over the electrode layer 501, PCPPn and MoO ₃ were co-deposited so that the weight ratio (PCPPn: MoO ₃ ) was 1: 0.5 and the thickness was 20 nm.

<2-3. Characteristics of light emitting element>
Next, FIG. 30 shows current efficiency-luminance characteristics of the light-emitting element 1 and the light-emitting element 2 manufactured as described above. Note that each light-emitting element was measured at room temperature (atmosphere kept at 23 ° C.).

Table 5 shows element characteristics of the light-emitting elements 1 and ² around 1000 cd / m ² .

In addition, FIG. 31 shows an electroluminescence spectrum when current was passed through the light-emitting element 1 and the light-emitting element 2 at a current density of ^2.5 mA / cm ² .

  As shown in FIGS. 30, 31, and Table 5, green light emission with high current efficiency and high color purity was obtained from the light emitting element 1 and the light emitting element 2. Therefore, a light-emitting element that emits light with high current efficiency can be obtained by forming the electrode layer 501 using an oxide layer containing In and a stabilizer Ga.

  Furthermore, since the light-emitting element 2 has higher current efficiency than the light-emitting element 1 and is driven at a lower driving voltage, it has been found that it is more preferable that the content of Ga as a stabilizer is larger than that of In.

  As described above, by using the structure of one embodiment of the present invention, a light-emitting element that exhibits high current efficiency and is driven at a low driving voltage can be manufactured.

  As described above, the structure described in this example can be combined with any of the other examples and embodiments as appropriate.

  In this example, manufacturing examples of light-emitting elements (light-emitting elements 3 to 5) which are one embodiment of the present invention will be described. FIG. 29B is a schematic cross-sectional view of a light-emitting element manufactured in this example, and Table 6 and Table 7 show details of the element structure. The compounds used are the same as in Example 2.

<3-1. Production of Light-Emitting Element 3>
The light-emitting element 3 is different from the light-emitting element 1 shown in Example 2 only in the following steps, and the other steps are the same as those for the light-emitting element 1.

  As the oxide layer 501b in contact with the conductive layer 501a included in the electrode layer 501, an In—Ga—Zn oxide was formed to a thickness of 10 nm. At this time, the atomic ratio of the metal element of the sputtering target was In: Ga: Zn = 1: 3: 6, and the substrate temperature was 300 ° C.

  Next, an ITSO film having a thickness of 10 nm was formed as a transparent conductive film 501c over the oxide layer 501b.

Further, as a hole injection layer 531 over the electrode layer 501, PCPPn and MoO ₃ were co-deposited so that the weight ratio (PCPPn: MoO ₃ ) was 1: 0.5 and the thickness was 9 nm.

<3-2. Production of Light-Emitting Element 4>
The light emitting element 4 is different from the manufacturing of the light emitting element 3 only in the following steps, and the other steps are the same as the manufacturing method of the light emitting element 3.

  As the oxide layer 501b in contact with the conductive layer 501a included in the electrode layer 501, an In—Ga—Zn oxide was formed to a thickness of 10 nm. At this time, the atomic ratio of the metal element of the sputtering target was In: Ga: Zn = 1: 3: 4, and the substrate temperature was 200 ° C.

  Note that in the light-emitting element 4, the transparent conductive film 501c was not formed over the oxide layer 501b, and the electrode layer 501 was configured with the conductive layer 501a and the oxide layer 501b.

Subsequently, as a hole injection layer 531 on the electrode layer 501, PCPPn and MoO ₃ were co-deposited so that the weight ratio (PCPPn: MoO ₃ ) was 1: 0.5 and the thickness was 22.5 nm.

<3-3. Production of Light-Emitting Element 5>
The light emitting element 5 is different from the manufacturing of the light emitting element 3 only in the following steps, and the other processes are the same as the manufacturing method of the light emitting element 3.

  An Al—Ni—La film was formed to a thickness of 200 nm as the conductive layer 503a included in the electrode layer 503 over the substrate 510.

  A Ti film was formed to a thickness of 6 nm as the oxide layer 503b in contact with the conductive layer 503a. After the Ti film was formed, a baking process was performed at 300 ° C. for 1 hour to oxidize the Ti film and form a titanium oxide film.

  Next, an ITSO film having a thickness of 10 nm was formed as a transparent conductive film 503c over the oxide layer 503b. Through the above process, the electrode layer 503 was formed.

Further, as a hole injection layer 531 over the electrode layer 503, PCPPn and MoO ₃ were co-deposited so that the weight ratio (PCPPn: MoO ₃ ) was 1: 0.5 and the thickness was 5 nm.

  Note that a blue color filter was formed as the optical element 514 on the sealing substrate 512 of the light-emitting elements 3 to 5.

<3-4. Characteristics of light emitting element>
Next, FIG. 32 shows current efficiency-luminance characteristics of the light-emitting elements 3 to 5 manufactured as described above. Further, FIG. 33 shows luminance-voltage characteristics. Note that each light-emitting element was measured at room temperature (atmosphere kept at 23 ° C.).

Table 8 shows element characteristics of the light-emitting elements 3 to 5 around 1000 cd / m ² .

In addition, FIG. 34 shows an electroluminescence spectrum when current is supplied to the light-emitting elements 3 to 5 at a current density of ^2.5 mA / cm ² .

  As shown in FIGS. 32 to 34 and Table 8, the light-emitting element 3 and the light-emitting element 4 had higher current efficiency than the light-emitting element 5 while emitting blue light with high color purity. As described in Example 1, the electrode structure including the In—Ga—Zn oxide of one embodiment of the present invention has high reflectance, and particularly has excellent reflectance in a blue region. Therefore, it was found that the electrode structure used for the light-emitting element 3 and the light-emitting element 4 is particularly suitable for a light-emitting element that exhibits blue light.

  As described above, by using the structure of one embodiment of the present invention, a light-emitting element having high current efficiency could be manufactured.

  As described above, the structure described in this example can be combined with any of the other examples and embodiments as appropriate.

  In this example, manufacturing examples of light-emitting elements (light-emitting elements 6 to 8) which are one embodiment of the present invention will be described. FIG. 29C is a schematic cross-sectional view of a light-emitting element manufactured in this example, and Table 9 shows details of the element structure. The structures and abbreviations of the compounds used are shown below.

<4-1. Production of Light-Emitting Element 6>
An Al—Ni—La film was formed to a thickness of 200 nm as the conductive layer 501a included in the electrode layer 501 over the substrate 510.

  Next, an In—Ga—Zn oxide was formed to a thickness of 10 nm as the oxide layer 501b in contact with the conductive layer 501a. At this time, the atomic ratio of the metal element of the sputtering target was In: Ga: Zn = 1: 3: 6, and the substrate temperature was 300 ° C.

Next, an ITSO film having a thickness of 10 nm was formed as a transparent conductive film 501c over the oxide layer 501b. The electrode layer 501 was formed by the above process. The electrode area of the electrode layer 501 was 4 mm ² (2 mm × 2 mm).

Next, as a hole injection layer 531 on the electrode layer 501, and DBT3P-II, the weight ratio of the _{MoO 3 (DBT3P-II: MoO} 3) is 1: 0.5, so that the thickness becomes 25nm codeposition did.

  Next, PCPPn was deposited as a hole transport layer 532 on the hole injection layer 531 so as to have a thickness of 10 nm.

Next, 7- [4- (10-phenyl-9-anthryl) phenyl] -7H-dibenzo [c, g] carbazole (cgDBCzPA), 1,6 mM emFLPAPrn, and the light emitting layer 520 are formed over the hole transport layer 532. Was co-evaporated so that the weight ratio (cgDBCzPA: 1,6 mM emFLPAPrn) was 1: 0.02 and the thickness was 10 nm. In the first layer of the light-emitting layer 520, cgDBCzPA is a host material, and 1,6 mM emFLPAPrn is a guest material (fluorescent material). Furthermore, 2mDBTBPDBq-II and N- (1,1′-biphenyl-4-yl) -N- [4- (9-phenyl-9H-carbazol-3-yl) phenyl] -9,9-dimethyl-9H -Fluorene-2-amine (abbreviation: PCBBiF) was co-deposited so that the weight ratio (2mDBTBPDBq-II: PCBBiF) was 0.4: 0.6 and the thickness was 2 nm. Furthermore, 2mDBTBPDBq-II, PCBBiF, (acetylacetonato) bis [5-methyl-6- (2-methylphenyl) -4-phenylpyrimidinato] iridium (III) (abbreviation: Ir (mpmppm) ₂ ( acac)) was co-deposited so that the weight ratio (2mDBTBPDBq-II: PCBiF: Ir (mpmppm) ₂ (acac)) was 0.8: 0.2: 0.06 and the thickness was 20 nm. Note that in the third layer of the light-emitting layer 520, 2mDBTBPDBq-II and PCBBiF are host materials, and Ir (mpmppm) ₂ (acac) is a guest material (phosphorescent material).

  Next, 2mDBTBPDBq-II and Bphen were sequentially deposited on the light-emitting layer 520 as the electron transport layer 533 so that the thicknesses thereof were 20 nm and 15 nm, respectively.

Next, Li ₂ O and CuPc were deposited as an electron injection layer 534 on the electron transport layer 533 so that the thicknesses were 0.1 nm and 2 nm, respectively. Thereafter, as the buffer layer 540, and DBT3P-II, the weight ratio of the _{MoO 3 (DBT3P-II: MoO} 3) is 1: 0.5, were co-deposited so that the thickness becomes 30 nm.

  Next, an ITO film was formed as an electrode layer 502 on the buffer layer 540 so as to have a thickness of 70 nm.

  Through the above steps, a structure formed over the substrate 510 was manufactured. Note that, in the above-described film formation process, evaporation was all performed by a resistance heating method, and the ITO film of the electrode layer 502 was formed by a sputtering method.

Next, the light emitting element 6 was sealed by fixing the sealing substrate on the substrate 510 using an organic EL sealing material in a glove box in a nitrogen atmosphere. Specifically, a sealing material is applied to the periphery of the light-emitting element, the substrate 510 and the sealing substrate are bonded, and ultraviolet light having a wavelength of 365 nm is irradiated with 6 J / cm ² and heat-treated at 80 ° C. for 1 hour. . The light emitting element 6 was obtained through the above steps.

<4-2. Production of Light-Emitting Element 7>
The light-emitting element 7 is different from the above-described production of the light-emitting element 6 only in the following steps, and the other steps are the same as those for the light-emitting element 6.

  As the oxide layer 501b in contact with the conductive layer 501a included in the electrode layer 501, an In—Ga—Zn oxide was formed to a thickness of 10 nm. At this time, the atomic ratio of the metal element of the sputtering target was In: Ga: Zn = 1: 3: 4, and the substrate temperature was 200 ° C.

  Note that in the light-emitting element 7, the transparent conductive film 501c was not formed over the oxide layer 501b, and the electrode layer 501 was configured with the conductive layer 501a and the oxide layer 501b.

Subsequently, as a hole injection layer 531 on the electrode layer 501, and DBT3P-II, the weight ratio of the _{MoO 3 (DBT3P-II: MoO} 3) is 1: 0.5, so that the thickness becomes 35nm codeposition did.

<4-3. Production of Light-Emitting Element 8>
The light-emitting element 8 is different from the manufacturing of the light-emitting element 6 only in the following steps, and the other manufacturing steps are the same as the manufacturing method of the light-emitting element 6.

  An Al—Ni—La film was formed to a thickness of 200 nm as the conductive layer 503a included in the electrode layer 503 over the substrate 510.

  A Ti film was formed to a thickness of 6 nm as the oxide layer 503b in contact with the conductive layer 503a. After the Ti film was formed, a baking process was performed at 300 ° C. for 1 hour to oxidize the Ti film and form a titanium oxide film.

  Next, an ITSO film having a thickness of 10 nm was formed as a transparent conductive film 503c over the oxide layer 503b. Through the above process, the electrode layer 503 was formed.

Further, as the hole injecting layer 531 on the electrode layer 503, and DBT3P-II, the weight ratio of the _{MoO 3 (DBT3P-II: MoO} 3) is 1: 0.5, were co-deposited so that the thickness is 25nm .

<4-4. Characteristics of light emitting element>
Next, FIG. 35 shows current efficiency-luminance characteristics of the light-emitting elements 6 to 8 manufactured as described above. In addition, FIG. 36 shows luminance-voltage characteristics. Note that each light-emitting element was measured at room temperature (atmosphere kept at 23 ° C.).

Table 10 shows element characteristics of the light-emitting elements 6 to 8 around 1000 cd / m ² .

In addition, FIG. 37 shows an electroluminescence spectrum obtained when current flows through the light-emitting elements 6 to 8 at a current density of ^2.5 mA / cm ² .

  As shown in FIGS. 35 and 36 and Table 10, the light-emitting element 6 and the light-emitting element 7 exhibited higher current efficiency than the light-emitting element 8. In particular, the light-emitting element 7 has high current efficiency.

  In addition, as shown in FIG. 37, it can be seen that the light-emitting element 6 and the light-emitting element 7 emit light in the yellow region more intensely than in the blue region. As a result, the chromaticity y increases in the order of the light emitting element 8, the light emitting element 6, and the light emitting element 7. In particular, the light emitting element 7 has a chromaticity closer to yellow than the light emitting element 8. Therefore, a light-emitting element having a region having different emission colors by including the electrode structure including the In—Ga—Zn oxide of one embodiment of the present invention and the electrode structure including an oxide different from the oxide is provided. It turns out that it is obtained.

  As described above, with the use of the structure of one embodiment of the present invention, a light-emitting element having high emission efficiency and having regions exhibiting different emission colors could be manufactured.

  As described above, the structure described in this example can be combined with any of the other examples and embodiments as appropriate.

100 EL layer 101 Electrode layer 101a Conductive layer 101b Oxide layer 101c Transparent conductive film 101d Oxide layer 101e Transparent conductive film 102 Electrode layer 103 Electrode layer 103a Conductive layer 103b Oxide layer 103c Transparent conductive film 104 Electrode layer 104a Conductive layer 104b Oxidation Physical layer 106 light emitting unit 108 light emitting unit 111 hole injection layer 112 hole transport layer 113 electron transport layer 114 electron injection layer 115 charge generation layer 116 hole injection layer 117 hole transport layer 118 electron transport layer 119 electron injection layer 120 light emission Layer 120a light emitting layer 120b light emitting layer 121 light emitting layer 121a light emitting layer 121b light emitting layer 122 light emitting layer 122a light emitting layer 122b light emitting layer 140 partition 150 light emitting element 170 light emitting element 172 light emitting element 174 light emitting element 176 light emitting element 190 tandem light emitting element 200 substrate 21 0A area 210B area 211A area 211B area 212A area 212B area 213A area 213B area 220 substrate 221B area 221G area 221R area 223 light shielding layer 224B optical element 224G optical element 224R optical element 250 light emitting element 270 light emitting element 280 light emitting element 282 light emitting element 282 Element 292 Light emitting element 400 EL layer 401 Electrode layer 401a Conductive layer 401b Oxide layer 402 Electrode layer 411 Hole injection layer 412 Hole transport layer 413 Light emission layer 414 Light emission layer 415 Electron transport layer 416 Electron injection layer 421 Guest material 422 Host material 431 Guest material 432 Organic compound 433 Organic compound 450 Light-emitting element 501 Electrode layer 501a Conductive layer 501b Oxide layer 501c Transparent conductive film 502 Electrode layer 503 Electrode layer 503a Conductive layer 503b Oxide layer 503c Transparent conductive film 510 Substrate 512 Sealing substrate 514 Optical element 520 Light emitting layer 521 Light emitting layer 522 Light emitting layer 531 Hole injection layer 532 Hole transport layer 533 Electron transport layer 534 Electron injection layer 535 Charge generation layer 537 Hole Transport layer 538 Electron transport layer 539 Electron injection layer 540 Buffer layer 600 Display device 601 Signal line driver circuit portion 602 Pixel portion 603 Scan line driver circuit portion 604 Sealing substrate 605 Seal material 607 Region 608 Wiring 609 FPC
610 element substrate 611 transistor 612 transistor 613 lower electrode 614 partition 616 EL layer 617 upper electrode 618 light emitting element 621 optical element 622 light shielding layer 623 transistor 624 transistor 801 pixel circuit 802 pixel unit 804 driving circuit unit 804a scanning line driving circuit 804b signal line driving Circuit 806 Protection circuit 807 Terminal portion 852 Transistor 854 Transistor 862 Capacitance element 872 Light emitting element 1001 Substrate 1002 Base insulating film 1003 Gate insulating film 1006 Gate electrode 1007 Gate electrode 1008 Gate electrode 1020 Interlayer insulating film 1021 Interlayer insulating film 1022 Electrode 1024B Lower electrode 1024G Lower electrode 1024R Lower electrode 1025 Partition 1026 Upper electrode 1028 EL layer 1029 Sealing layer 1031 Sealing substrate 1032 Seal material 1033 Base material 1034B Colored layer 1034G Colored layer 1034R Colored layer 1035 Light-shielding layer 1036 Overcoat layer 1037 Interlayer insulating film 1040 Pixel portion 1041 Drive circuit portion 1042 Peripheral portion 2000 Touch panel 2001 Touch panel 2501 Display device 2502R Pixel 2502t Transistor 2503c Capacitance element 2503g Scan line driver circuit 2503s Signal line driver circuit 2503t Transistor 2509 FPC
2510 Substrate 2510a Insulating layer 2510b Flexible substrate 2510c Adhesive layer 2511 Wiring 2519 Terminal 2521 Insulating layer 2528 Partition 2550R Light emitting element 2560 Sealing layer 2567BM Light shielding layer 2567p Antireflection layer 2567R Colored layer 2570 Substrate 2570a Insulating layer 2570b Flexible substrate 2570c Adhesive layer 2580R Light emitting module 2590 Substrate 2591 Electrode 2592 Electrode 2593 Insulating layer 2594 Wiring 2595 Touch sensor 2597 Adhesive layer 2598 Wiring 2599 Connection layer 2601 Pulse voltage output circuit 2602 Current detection circuit 2603 Capacitance 2611 Transistor 2612 Transistor 2613 Transistor 2621 Electrode 2622 Electrode 8000 Display Module 8001 Upper cover 8002 Lower cover 8003 FPC
8004 Touch sensor 8005 FPC
8006 Display device 8009 Frame 8010 Printed circuit board 8011 Battery 8501 Illumination device 8502 Illumination device 8503 Illumination device 8504 Illumination device 9000 Case 9001 Display unit 9003 Speaker 9005 Operation key 9006 Connection terminal 9007 Sensor 9008 Microphone 9050 Operation button 9051 Information 9052 Information 9053 Information 9054 Information 9055 hinge 9100 portable information terminal 9101 portable information terminal 9102 portable information terminal 9200 portable information terminal 9201 portable information terminal

Claims (21)

A first electrode layer;
A second electrode layer;
An EL layer provided between the first electrode layer and the second electrode layer;
A light emitting device comprising:
The first electrode layer includes
A conductive layer;
An oxide layer in contact with the conductive layer,
The conductive layer has a function of reflecting light,
The oxide layer is
In and M (M represents Al, Si, Ti, Ga, Y, Zr, Sn, La, Ce, Nd, or Hf),
The content of M contained in the oxide layer is not less than the content of In.
A light emitting element characterized by the above. A first electrode layer;
An EL layer on the first electrode layer;
A second electrode layer on the EL layer;
A light emitting device comprising:
The first electrode layer includes
A conductive layer;
An oxide layer in contact with the conductive layer,
The conductive layer has a function of reflecting light,
The oxide layer is
In and M (M represents Al, Si, Ti, Ga, Y, Zr, Sn, La, Ce, Nd, or Hf),
The content of M contained in the oxide layer is not less than the content of In.
A light emitting element characterized by the above. A first electrode layer;
An EL layer in contact with the first electrode layer;
A second electrode layer in contact with the EL layer;
A light emitting device comprising:
The first electrode layer includes
A conductive layer;
An oxide layer in contact with the conductive layer,
The conductive layer has a function of reflecting light,
The oxide layer is
In and M (M represents Al, Si, Ti, Ga, Y, Zr, Sn, La, Ce, Nd, or Hf),
The content of M contained in the oxide layer is not less than the content of In.
A light emitting element characterized by the above. A first electrode layer;
A second electrode layer;
A third electrode layer;
An EL layer;
A light emitting device comprising:
The EL layer is
Provided between the first electrode layer and the second electrode layer, and between the second electrode layer and the third electrode layer;
The first electrode layer includes
A conductive layer;
An oxide layer in contact with the conductive layer,
The conductive layer has a function of reflecting light,
The oxide layer is
In and M (M represents Al, Si, Ti, Ga, Y, Zr, Sn, La, Ce, Nd, or Hf),
The content of M contained in the oxide layer is not less than the content of In.
A light emitting element characterized by the above. A first electrode layer;
An EL layer on the first electrode layer;
A second electrode layer on the EL layer;
A third electrode layer;
A light emitting device comprising:
The EL layer is
Provided on the third electrode layer;
The first electrode layer includes
A conductive layer;
An oxide layer in contact with the conductive layer,
The conductive layer has a function of reflecting light,
The oxide layer is
In and M (M represents Al, Si, Ti, Ga, Y, Zr, Sn, La, Ce, Nd, or Hf),
The content of M contained in the oxide layer is not less than the content of In.
A light emitting element characterized by the above. A first electrode layer;
An EL layer in contact with the first electrode layer;
A second electrode layer in contact with the EL layer;
A light emitting device having a third electrode layer,
The EL layer is
Provided in contact with the third electrode layer;
The first electrode layer includes
A conductive layer;
An oxide layer on the conductive layer in contact with the conductive layer,
The conductive layer has a function of reflecting light,
The oxide layer is
In and M (M represents Al, Si, Ti, Ga, Y, Zr, Sn, La, Ce, Nd, or Hf),
The content of M contained in the oxide layer is not less than the content of In.
A light emitting element characterized by the above. In any one of Claims 4 thru | or 6,
The third electrode layer includes
Having an oxide different from that of the oxide layer,
A light emitting element characterized by the above. In any one of Claims 4 thru | or 7,
The first region sandwiched between the first electrode layer and the second electrode layer is:
The second region sandwiched between the second electrode layer and the third electrode layer can exhibit light of a color different from the color of light that can be exhibited by the second region,
A light emitting element characterized by the above. In any one of Claims 1 thru | or 8,
The EL layer has a first light emitting layer and a second light emitting layer,
The first light emitting layer has a first compound having a function of exhibiting light,
The second light emitting layer has a second compound having a function of exhibiting light.
A light emitting element characterized by the above. In claim 9,
One of the first compound and the second compound has a function of converting singlet excitation energy into light emission,
The other of the first compound and the second compound has a function of converting triplet excitation energy into light emission.
A light emitting element characterized by the above. In claim 9 or claim 10,
The first compound exhibits light of a color different from the color of light exhibited by the second compound.
A light emitting element characterized by the above. In any one of Claims 1 to 11,
The conductive layer comprises Al or Ag;
A light emitting element characterized by the above. In any one of Claims 1 to 12,
The second electrode layer includes
Having at least one of In, Ag, Mg,
A light emitting element characterized by the above. In any one of Claims 1 thru / or Claim 13,
The oxide layer is
Furthermore, it has Zn,
A light emitting element characterized by the above. In any one of Claims 1 thru | or 14,
The M is Ga;
A light emitting element characterized by the above. In any one of Claims 1 to 15,
The oxide layer includes In, Ga, and Zn. A display device comprising the light emitting device according to any one of claims 1 to 16,
The display device
Having a transistor for switching the light emitting element;
The transistor includes an oxide semiconductor layer in a channel formation region;
The oxide semiconductor layer is
In and M (M represents Al, Si, Ti, Ga, Y, Zr, Sn, La, Ce, Nd, or Hf),
A display device characterized by that. In claim 17,
The oxide layer and the oxide semiconductor layer have the same element,
A display device characterized by that. The light emitting device according to any one of claims 1 to 18,
With color filters or transistors,
A display device. A display device according to any one of claims 17 to 19,
A housing or touch sensor;
Electronic equipment having The light emitting device according to any one of claims 1 to 16,
A housing or touch sensor;
A lighting device.